[bfcache] Pause PausableScriptExecutor for frozen context

This CL makes PausableScriptExecutor pause and post tasks to execute
scripts instead of synchronously running, when the context is frozen.

We saw a big increase of JavaScript execution in　bfcache that caused eviction. This was coming from extensions[1].

The users of PausableScriptExecutor are JSInjection and Extensions, and it makes sense to respect freezing for both of the cases.

[1]Design doc: https://docs.google.com/document/d/1uf5KOSHzVlh1zSE_PeCD1IxP_Fu-E5rS7jsLmpzCDVo/edit#

Bug: 1379227
Change-Id: If3b92ad9f8311190c4238d4c6d2d9f7291b7921f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3995288
Reviewed-by: Hiroshige Hayashizaki <hiroshige@chromium.org>
Reviewed-by: Yaron Friedman <yfriedman@chromium.org>
Commit-Queue: Yuzu Saijo <yuzus@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1067406}

chrome/browser/extensions/back_forward_cache_browsertest.cc

@@ -182,6 +182,10 @@ class ExtensionBackForwardCacheBrowserTest : public ExtensionBrowserTest {
     EXPECT_NE(u"fail", title);
   }
 
+  content::WebContents* web_contents() const {
+    return browser()->tab_strip_model()->GetActiveWebContents();
+  }
+
  protected:
   base::HistogramTester histogram_tester_;
 
@@ -994,19 +998,20 @@ IN_PROC_BROWSER_TEST_F(ExtensionBackForwardCacheBrowserTest,
   content::RenderFrameHostWrapper rfh_a(
       ui_test_utils::NavigateToURL(browser(), url_a));
 
-  // 2) Navigate to B.
+  // 2) Navigate to B. Ensure that |rfh_a| is in back/forward cache.
   ASSERT_TRUE(ui_test_utils::NavigateToURL(browser(), url_b));
-
-  // Expect that `rfh_a` is destroyed as loading page B will causes a storage
-  // event which is sent to all listeners. Since `rfh_a` is a listener but is in
-  // the back forward cache it gets evicted.
-  EXPECT_TRUE(rfh_a.WaitUntilRenderFrameDeleted());
-
-  // Validate also that the eviction reason is `kJavascriptExecution` due
-  // to the extension processing a callback while in the back forward cache.
-  EXPECT_EQ(1, histogram_tester_.GetBucketCount(
+  EXPECT_EQ(rfh_a->GetLifecycleState(),
+            content::RenderFrameHost::LifecycleState::kInBackForwardCache);
+  // Validate that the eviction due to JavaScript execution has not happened.
+  EXPECT_EQ(0, histogram_tester_.GetBucketCount(
                    "BackForwardCache.Eviction.Renderer",
                    blink::mojom::RendererEvictionReason::kJavaScriptExecution));
+
+  // 3) Navigate back to A and make sure that the callback is called after
+  // restore.
+  ASSERT_TRUE(content::HistoryGoBack(web_contents()));
+  EXPECT_EQ("called",
+            EvalJs(rfh_a.get(), "document.getElementById('callback').value;"));
 }
 
 // Test that allows all extensions but disables bfcache in the presence of a few

chrome/test/data/extensions/back_forward_cache/content_script_storage/storage.js

@@ -3,10 +3,13 @@
 // found in the LICENSE file.
 
 chrome.storage.onChanged.addListener((changes, area) => {
-  // do nothing
+  let input = document.createElement("input");
+  input.id = "callback"
+  input.value += "called";
+  document.documentElement.appendChild(input);
 });
 
 if (window.location.host.indexOf('b.com') != -1) {
   var options = {test: true};
   chrome.storage.sync.set({options});
-}
+}

third_party/blink/renderer/core/execution_context/execution_context.cc

@@ -347,7 +347,7 @@ LoaderFreezeMode ExecutionContext::GetLoaderFreezeMode() const {
   return LoaderFreezeMode::kNone;
 }
 
-bool ExecutionContext::IsLoadDeferred() const {
+bool ExecutionContext::IsContextFrozenOrPaused() const {
   return lifecycle_state_ == mojom::blink::FrameLifecycleState::kPaused ||
          lifecycle_state_ == mojom::blink::FrameLifecycleState::kFrozen;
 }

third_party/blink/renderer/core/execution_context/execution_context.h

@@ -283,7 +283,7 @@ class CORE_EXPORT ExecutionContext : public Supplementable<ExecutionContext>,
   mojom::FrameLifecycleState ContextPauseState() const {
     return lifecycle_state_;
   }
-  bool IsLoadDeferred() const;
+  bool IsContextFrozenOrPaused() const;
 
   // Gets the next id in a circular sequence from 1 to 2^31-1.
   int CircularSequentialID();

third_party/blink/renderer/core/frame/pausable_script_executor.cc

@@ -320,7 +320,7 @@ PausableScriptExecutor::~PausableScriptExecutor() = default;
 void PausableScriptExecutor::Run() {
   ExecutionContext* context = GetExecutionContext();
   DCHECK(context);
-  if (!context->IsContextPaused()) {
+  if (!context->IsContextFrozenOrPaused()) {
     ExecuteAndDestroySelf();
     return;
   }