Rollback of 5884e77 because it breaks some Google-internal code.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=152956678

src/com/google/javascript/jscomp/DefaultPassConfig.java

@@ -535,7 +535,6 @@ protected List<PassFactory> getOptimizations() {
       return passes;
     }
 
-    passes.add(hoistVars);
     passes.add(normalize);
 
     // Create extern exports after the normalize because externExports depends on unique names.
@@ -2591,13 +2590,6 @@ protected CompilerPass create(final AbstractCompiler compiler) {
     }
   };
 
-  private final PassFactory hoistVars = new PassFactory("hoistVars", true) {
-    @Override
-    protected CompilerPass create(AbstractCompiler compiler) {
-      return new HoistVarsOutOfBlocks(compiler);
-    }
-  };
-
   private final PassFactory normalize = new PassFactory("normalize", true) {
     @Override
     protected CompilerPass create(AbstractCompiler compiler) {

src/com/google/javascript/jscomp/Denormalize.java

@@ -19,11 +19,6 @@
 import static com.google.common.base.Preconditions.checkState;
 
 import com.google.javascript.jscomp.NodeTraversal.Callback;
-import com.google.javascript.jscomp.ReferenceCollectingCallback.Behavior;
-import com.google.javascript.jscomp.ReferenceCollectingCallback.Reference;
-import com.google.javascript.jscomp.ReferenceCollectingCallback.ReferenceCollection;
-import com.google.javascript.jscomp.ReferenceCollectingCallback.ReferenceMap;
-import com.google.javascript.rhino.IR;
 import com.google.javascript.rhino.Node;
 import com.google.javascript.rhino.Token;
 
@@ -32,22 +27,16 @@
  * not handled by other passes (such as CollapseVariableDeclarations) to avoid making the resulting
  * code larger.
  *
- * <p>Currently this pass only does a few things:
+ * <p>Currently this pass only does two things:
  *
- * <p>1. Push statements into for-loop initializer. This: var a = 0; for(;a<0;a++) {} becomes:
- * for(var a = 0;a<0;a++) {}
+ * <p>1. Push statements into for-loop initializer. This: <pre>var a = 0; for(;a<0;a++) {}</pre>
+ * becomes: <pre>for(var a = 0;a<0;a++) {}</pre>
  *
  * <p>2. Fold assignments like x = x + 1 into x += 1
  *
- * <p>3. Inline 'var' keyword. For instance: <code>
- *   var x;
- *   if (y) { x = 0; }
- * </code> becomes <code>if (y) { var x = 0; }</code>, effectively undoing what {@link
- * Normalize.HoistVarsOutOfBlocks} does.
- *
  * @author johnlenz@google.com (johnlenz)
  */
-class Denormalize implements CompilerPass, Callback, Behavior {
+class Denormalize implements CompilerPass, Callback {
 
   private final AbstractCompiler compiler;
 
@@ -58,59 +47,13 @@ class Denormalize implements CompilerPass, Callback, Behavior {
   @Override
   public void process(Node externs, Node root) {
     NodeTraversal.traverseEs6(compiler, root, this);
-    // Don't inline the VAR declaration if this compilation involves old-style ctemplates.
-    if (compiler.getOptions().syntheticBlockStartMarker == null) {
-      (new ReferenceCollectingCallback(compiler, this, new Es6SyntacticScopeCreator(compiler)))
-          .process(root);
-    }
   }
 
   @Override
   public boolean shouldTraverse(NodeTraversal t, Node n, Node parent) {
     return true;
   }
 
-  /**
-   * Implements step 3 (inlining the var keyword).
-   */
-  @Override
-  public void afterExitScope(NodeTraversal t, ReferenceMap referenceMap) {
-    if (t.getScopeRoot().isNormalBlock() && t.getScopeRoot().getParent().isFunction()) {
-      for (Var v : t.getScope().getVarIterable()) {
-        ReferenceCollection references = referenceMap.getReferences(v);
-        Reference declaration = null;
-        Reference assign = null;
-        for (Reference r : references) {
-          if (r.isVarDeclaration()
-              && NodeUtil.isStatement(r.getNode().getParent())
-              && !r.isInitializingDeclaration()) {
-            declaration = r;
-          } else if (assign == null
-              && r.isSimpleAssignmentToName()
-              && r.getScope().getClosestHoistScope().equals(t.getScope())) {
-            assign = r;
-          }
-        }
-        if (declaration != null && assign != null) {
-          Node lhs = assign.getNode();
-          Node assignNode = lhs.getParent();
-          if (assignNode.getParent().isExprResult()) {
-            Node rhs = lhs.getNext();
-            assignNode
-                .getGrandparent()
-                .replaceChild(assignNode.getParent(), IR.var(lhs.detach(), rhs.detach()));
-
-            checkState(
-                declaration.getNode().getParent().isVar(), declaration.getNode().getParent());
-            NodeUtil.removeChild(declaration.getNode().getParent(), declaration.getNode());
-
-            compiler.reportCodeChange();
-          }
-        }
-      }
-    }
-  }
-
   @Override
   public void visit(NodeTraversal t, Node n, Node parent) {
     maybeCollapseIntoForStatements(n, parent);

src/com/google/javascript/rhino/Node.java

@@ -1565,16 +1565,6 @@ public Node getAncestor(int level) {
     return node;
   }
 
-  /** @return True if this Node is {@code node} or a descendant of {@code node}. */
-  public boolean isDescendantOf(Node node) {
-    for (Node n = this; n != null; n = n.parent) {
-      if (n == node) {
-        return true;
-      }
-    }
-    return false;
-  }
-
   /**
    * Iterates all of the node's ancestors excluding itself.
    */

test/com/google/javascript/jscomp/DenormalizeTest.java

@@ -42,40 +42,6 @@ protected int getNumRepetitions() {
     return 1;
   }
 
-  public void testInlineVarKeyword1() {
-    test(
-        LINE_JOINER.join(
-            "function f() {",
-            "  var x;",
-            "  function g() { x = 2; }",
-            "  if (y) { x = -1; }",
-            "  alert(x);",
-            "}"),
-        LINE_JOINER.join(
-            "function f() {",
-            "  function g() { x = 2; }",
-            "  if (y) { var x = -1; }",
-            "  alert(x);",
-            "}"));
-  }
-
-  public void testInlineVarKeyword2() {
-    test(
-        LINE_JOINER.join(
-            "function f() {",
-            "  var x;",
-            "  function g() { x = 2; }",
-            "  if (y) { x = -1; } else { x = 3; }",
-            "  alert(x);",
-            "}"),
-        LINE_JOINER.join(
-            "function f() {",
-            "  function g() { x = 2; }",
-            "  if (y) { var x = -1; } else { x = 3; }",
-            "  alert(x);",
-            "}"));
-  }
-
   public void testFor() {
     // Verify assignments are moved into the FOR init node.
     test("a = 0; for(; a < 2 ; a++) foo()",
@@ -178,7 +144,7 @@ public NormalizeAndDenormalizePass(AbstractCompiler compiler) {
     @Override
     public void process(Node externs, Node root) {
       NodeTraversal.traverseEs6(compiler, root, normalizePass);
-      denormalizePass.process(externs, root);
+      NodeTraversal.traverseEs6(compiler, root, denormalizePass);
     }
   }