aw: Fix lost invalidate while playing video

android_webview/browser/browser_view_renderer.cc

Index: android_webview/browser/browser_view_renderer.cc
diff --git a/android_webview/browser/browser_view_renderer.cc b/android_webview/browser/browser_view_renderer.cc
index 2fc80229d695b718382f778f1c84ef7e48e0432e..e71482a4a06d6c5711c020f9dc672f434d3b1867 100644
--- a/android_webview/browser/browser_view_renderer.cc
+++ b/android_webview/browser/browser_view_renderer.cc
@@ -664,6 +664,7 @@ void BrowserViewRenderer::EnsureContinuousInvalidation(bool force_invalidate) {
   if (throttle_fallback_tick)
     return;
 
+  base::AutoLock lock(render_thread_lock_);
   block_invalidates_ = compositor_needs_continuous_invalidate_;
 
   // Unretained here is safe because the callback is cancelled when
@@ -713,9 +714,21 @@ bool BrowserViewRenderer::CompositeSW(SkCanvas* canvas) {
 }
 
 void BrowserViewRenderer::DidComposite(bool force_invalidate) {
-  fallback_tick_.Cancel();
-  block_invalidates_ = false;
-  EnsureContinuousInvalidation(force_invalidate);
+  {
+    base::AutoLock lock(render_thread_lock_);
+    fallback_tick_.Cancel();

[mkosiba (inactive), 2014/05/12 14:29:51]

this doesn't look threadsafe:

from base/cancellable_callback.h

"CancelableCallback objects must be created on, posted to, cancelled on, and
destroyed on the same thread."

[boliu, 2014/05/12 15:34:49]

Hmm, good point. There is nothing protecting running the callback.

Moved to UI thread instead. Cancelling shouldn't matter other than a few
unnecessary fallback ticks.

+    block_invalidates_ = false;
+  }
+
+  if (ui_task_runner_->BelongsToCurrentThread()) {
+    EnsureContinuousInvalidation(force_invalidate);
+    return;
+  }
+  ui_task_runner_->PostTask(
+      FROM_HERE,
+      base::Bind(&BrowserViewRenderer::EnsureContinuousInvalidation,
+                 ui_thread_weak_ptr_,
+                 force_invalidate));
 }
 
 std::string BrowserViewRenderer::ToString(AwDrawGLInfo* draw_info) const {