[Paint Holding] Only defer commits once per document

Add a flag to LocalFrameView to prevent multiple lifecycle starts
causing multiple commit deferrals.

Bug: 974280
Change-Id: Id70132f9b8ff528d96be110c4e383b3054befa55
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1663252Reviewed-by: vmpstr <vmpstr@chromium.org>
Commit-Queue: Stephen Chenney <schenney@chromium.org>
Auto-Submit: Stephen Chenney <schenney@chromium.org>
Cr-Commit-Position: refs/heads/master@{#670181}

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

@@ -1913,6 +1913,9 @@ void LocalFrameView::DidAttachDocument() {
 
     page->GlobalRootScrollerController().InitializeViewportScrollCallback(
         *root_frame_viewport, *frame_->GetDocument());
+
+    // Allow for commits to be deferred because this is a new document.
+    have_deferred_commits_ = false;
   }
 }
 
@@ -4146,8 +4149,17 @@ void LocalFrameView::BeginLifecycleUpdates() {
   if (document && base::FeatureList::IsEnabled(
                       blink::features::kAvoidFlashBetweenNavigation)) {
     if (document->DeferredCompositorCommitIsAllowed()) {
-      chrome_client.StartDeferringCommits(
-          GetCommitDelayForAvoidFlashBetweenNavigation());
+      // Only defer commits once. This method gets called multiple times,
+      // and we do not want to defer a second time if we have already done
+      // so once and resumed commits already.
+      if (!have_deferred_commits_) {
+        chrome_client.StartDeferringCommits(
+            GetCommitDelayForAvoidFlashBetweenNavigation());
+        have_deferred_commits_ = true;
+      }
+      // We do not StopDeferringCommits in cases where we have already started.
+      // A previously started deferral may not have completed yet, and we do
+      // not want to stop it prematurely.
     } else {
       chrome_client.StopDeferringCommits(
           cc::PaintHoldingCommitTrigger::kDisallowed);

third_party/blink/renderer/core/frame/local_frame_view.h

@@ -957,6 +957,10 @@ class CORE_EXPORT LocalFrameView final
   bool needs_focus_on_fragment_;
   bool in_lifecycle_update_;
 
+  // True if the frame has deferred commits at least once per document load.
+  // We won't defer again for the same document.
+  bool have_deferred_commits_ = false;
+
   LifecycleData lifecycle_data_;
 
   IntRect remote_viewport_intersection_;