backport various changes to make #1050 work

Author: crowell

net/instaweb/automatic/proxy_interface_test.cc

@@ -749,22 +749,25 @@ TEST_F(ProxyInterfaceTest, PassThroughEmptyResource) {
   ResponseHeaders response_headers;
   FetchFromProxy("text.txt", true, &text, &response_headers);
   EXPECT_EQ(kContent, text);
+  // HTTP resource not found the first time.
+  EXPECT_EQ(1, http_cache()->cache_misses()->Get());
+  EXPECT_EQ(0, http_cache()->cache_hits()->Get());
   // One lookup for ajax metadata and one for the HTTP response. Neither are
   // found.
   EXPECT_EQ(2, lru_cache()->num_misses());
-  EXPECT_EQ(1, http_cache()->cache_misses()->Get());
   EXPECT_EQ(0, lru_cache()->num_hits());
 
   ClearStats();
   GoogleString text2;
   ResponseHeaders response_headers2;
   FetchFromProxy("text.txt", true, &text2, &response_headers2);
   EXPECT_EQ(kContent, text2);
-  // The HTTP response is found but the ajax metadata is not found.
-  EXPECT_EQ(1, lru_cache()->num_hits());
-  EXPECT_EQ(1, http_cache()->cache_hits()->Get());
-  EXPECT_EQ(1, lru_cache()->num_misses());
-  EXPECT_EQ(0, http_cache()->cache_misses()->Get());
+  // Empty resources are not remembered in this flow, so stats are exactly the
+  // same on second load.
+  EXPECT_EQ(1, http_cache()->cache_misses()->Get());
+  EXPECT_EQ(0, http_cache()->cache_hits()->Get());
+  EXPECT_EQ(2, lru_cache()->num_misses());
+  EXPECT_EQ(0, lru_cache()->num_hits());
 }
 
 TEST_F(ProxyInterfaceTest, SetCookieNotCached) {

net/instaweb/rewriter/css_flatten_imports_test.cc

@@ -605,7 +605,7 @@ TEST_F(CssFlattenImportsTest, DontFlattenOverTinyLimit) {
 TEST_F(CssFlattenImportsTest, FlattenEmpty) {
   // We intentionally do not inline any empty resources.
   const char kFilename[] = "empty.css";
-  const char css_in[] = "@import url(http://test.com/empty.css);";
+  const char css_in[] = "@import url(http://test.com/empty.css) ;";
   const char empty_content[] = "";
 
   SetResponseWithDefaultHeaders(kFilename, kContentTypeCss, empty_content, 100);

net/instaweb/rewriter/inline_rewrite_context.cc

@@ -84,12 +84,8 @@ bool InlineRewriteContext::Partition(OutputPartitions* partitions,
 
   bool ok = false;
   GoogleString reason_for_failure;
-  if (!resource->IsSafeToRewrite(rewrite_uncacheable())) {
+  if (!resource->IsSafeToRewrite(rewrite_uncacheable(), &reason_for_failure)) {
     AddRecheckDependency();
-    // TODO(morlovich): Follow up by integrating with jmaessen's instrumentation
-    // of IsSafeToRewrite?
-    reason_for_failure =
-        "Can't inline since resource not fetchable or cacheable";
   } else {
     resource->AddInputInfoToPartition(Resource::kOmitInputHash, 0, partition);
     if (ShouldInline(resource, &reason_for_failure)) {