aw: Handle skipped hardware frame correctly

Render thread is still holding the previous frame, which can still be
used to draw in the functor. Update the android_webview bits of code to
handle this correctly. Return true from OnHardwareDraw when render
thread already has a previous frame.

BUG=526842

Review URL: https://codereview.chromium.org/1372193003

Cr-Commit-Position: refs/heads/master@{#351879}

6 files changed, 75 insertions, 2 deletions

diff --git a/android_webview/browser/browser_view_renderer.cc b/android_webview/browser/browser_view_renderer.cc
index 556feef..e9602d1 100644
--- a/android_webview/browser/browser_view_renderer.cc
+++ b/android_webview/browser/browser_view_renderer.cc
@@ -262,7 +262,7 @@ bool BrowserViewRenderer::CompositeHw() {
   if (!frame.get()) {
     TRACE_EVENT_INSTANT0("android_webview", "NoNewFrame",
                          TRACE_EVENT_SCOPE_THREAD);
-    return false;
+    return shared_renderer_state_.HasFrameOnUI();
   }
 
   scoped_ptr<ChildFrame> child_frame = make_scoped_ptr(
diff --git a/android_webview/browser/browser_view_renderer_unittest.cc b/android_webview/browser/browser_view_renderer_unittest.cc
index 9e2289c..5b2ec24 100644
--- a/android_webview/browser/browser_view_renderer_unittest.cc
+++ b/android_webview/browser/browser_view_renderer_unittest.cc
@@ -63,6 +63,7 @@ class TestAnimateInAndOutOfScreen : public RenderingTest {
   }
 
   void WillOnDraw() override {
+    RenderingTest::WillOnDraw();
     // Step 0: A single onDraw on screen. The parent draw constraints
     // of the BVR will updated to be the initial constraints.
     // Step 1: A single onDrraw off screen. The parent draw constraints of the
@@ -143,4 +144,46 @@ class TestAnimateInAndOutOfScreen : public RenderingTest {
 
 RENDERING_TEST_F(TestAnimateInAndOutOfScreen);
 
+class CompositorNoFrameTest : public RenderingTest {
+ public:
+  CompositorNoFrameTest() : on_draw_count_(0) {}
+
+  void StartTest() override {
+    browser_view_renderer_->PostInvalidate();
+  }
+
+  void WillOnDraw() override {
+    if (0 == on_draw_count_) {
+      // No frame from compositor.
+    } else if (1 == on_draw_count_) {
+      SetCompositorFrame();
+    } else if (2 == on_draw_count_) {
+      // No frame from compositor.
+    }
+    // There may be trailing invalidates.
+  }
+
+  void DidOnDraw(bool success) override {
+    if (0 == on_draw_count_) {
+      // Should fail as there has been no frames from compositor.
+      EXPECT_FALSE(success);
+      browser_view_renderer_->PostInvalidate();
+    } else if (1 == on_draw_count_) {
+      // Should succeed with frame from compositor.
+      EXPECT_TRUE(success);
+      browser_view_renderer_->PostInvalidate();
+    } else if (2 == on_draw_count_) {
+      // Should still succeed with last frame, even if no frame from compositor.
+      EXPECT_TRUE(success);
+      EndTest();
+    }
+    on_draw_count_++;
+  }
+
+ private:
+  int on_draw_count_;
+};
+
+RENDERING_TEST_F(CompositorNoFrameTest);
+
 }  // namespace android_webview
diff --git a/android_webview/browser/shared_renderer_state.cc b/android_webview/browser/shared_renderer_state.cc
index 69a41e5..e62c502 100644
--- a/android_webview/browser/shared_renderer_state.cc
+++ b/android_webview/browser/shared_renderer_state.cc
@@ -90,6 +90,7 @@ SharedRendererState::SharedRendererState(
     : ui_loop_(ui_loop),
       browser_view_renderer_(browser_view_renderer),
       renderer_manager_key_(GLViewRendererManager::GetInstance()->NullKey()),
+      hardware_renderer_has_frame_(false),
       inside_hardware_release_(false),
       weak_factory_on_ui_thread_(this) {
   DCHECK(ui_loop_->BelongsToCurrentThread());
@@ -170,6 +171,8 @@ void SharedRendererState::SetCompositorFrameOnUI(scoped_ptr<ChildFrame> frame) {
 
 scoped_ptr<ChildFrame> SharedRendererState::PassCompositorFrameOnRT() {
   base::AutoLock lock(lock_);
+  hardware_renderer_has_frame_ =
+      hardware_renderer_has_frame_ || child_frame_.get();
   return child_frame_.Pass();
 }
 
@@ -278,6 +281,7 @@ void SharedRendererState::DrawGL(AwDrawGLInfo* draw_info) {
   }
 
   if (IsInsideHardwareRelease()) {
+    hardware_renderer_has_frame_ = false;
     hardware_renderer_.reset();
     // Flush the idle queue in tear down.
     DeferredGpuCommandService::GetInstance()->PerformAllIdleWork();
@@ -342,6 +346,11 @@ void SharedRendererState::ReleaseCompositorResourcesIfNeededOnUI(
   }
 }
 
+bool SharedRendererState::HasFrameOnUI() const {
+  base::AutoLock lock(lock_);
+  return hardware_renderer_has_frame_ || child_frame_.get();
+}
+
 void SharedRendererState::InitializeHardwareDrawIfNeededOnUI() {
   DCHECK(ui_loop_->BelongsToCurrentThread());
   GLViewRendererManager* manager = GLViewRendererManager::GetInstance();
diff --git a/android_webview/browser/shared_renderer_state.h b/android_webview/browser/shared_renderer_state.h
index 8969cef..dca3bcc 100644
--- a/android_webview/browser/shared_renderer_state.h
+++ b/android_webview/browser/shared_renderer_state.h
@@ -49,6 +49,7 @@ class SharedRendererState {
   bool ReturnedResourcesEmptyOnUI() const;
   scoped_ptr<ChildFrame> PassUncommittedFrameOnUI();
   void DeleteHardwareRendererOnUI();
+  bool HasFrameOnUI() const;
 
   // RT thread methods.
   gfx::Vector2d GetScrollOffsetOnRT();
@@ -95,6 +96,7 @@ class SharedRendererState {
 
   // Accessed by both UI and RT thread.
   mutable base::Lock lock_;
+  bool hardware_renderer_has_frame_;
   gfx::Vector2d scroll_offset_;
   scoped_ptr<ChildFrame> child_frame_;
   bool inside_hardware_release_;
diff --git a/android_webview/browser/test/rendering_test.cc b/android_webview/browser/test/rendering_test.cc
index 6b8e57e..4e37cf9 100644
--- a/android_webview/browser/test/rendering_test.cc
+++ b/android_webview/browser/test/rendering_test.cc
@@ -8,6 +8,7 @@
 #include "android_webview/browser/child_frame.h"
 #include "base/location.h"
 #include "base/thread_task_runner_handle.h"
+#include "cc/output/compositor_frame.h"
 #include "content/public/test/test_synchronous_compositor_android.h"
 
 namespace android_webview {
@@ -64,6 +65,23 @@ void RenderingTest::QuitMessageLoop() {
   message_loop_->QuitWhenIdle();
 }
 
+void RenderingTest::SetCompositorFrame() {
+  DCHECK(compositor_.get());
+  scoped_ptr<cc::CompositorFrame> compositor_frame(new cc::CompositorFrame);
+  scoped_ptr<cc::DelegatedFrameData> frame(new cc::DelegatedFrameData);
+  scoped_ptr<cc::RenderPass> root_pass(cc::RenderPass::Create());
+  gfx::Rect viewport(browser_view_renderer_->size());
+  root_pass->SetNew(cc::RenderPassId(1, 1), viewport, viewport,
+                    gfx::Transform());
+  frame->render_pass_list.push_back(root_pass.Pass());
+  compositor_frame->delegated_frame_data = frame.Pass();
+  compositor_->SetHardwareFrame(compositor_frame.Pass());
+}
+
+void RenderingTest::WillOnDraw() {
+  SetCompositorFrame();
+}
+
 bool RenderingTest::RequestDrawGL(bool wait_for_completion) {
   window_->RequestDrawGL(wait_for_completion);
   return true;
diff --git a/android_webview/browser/test/rendering_test.h b/android_webview/browser/test/rendering_test.h
index b3cdb4c..0d510ab 100644
--- a/android_webview/browser/test/rendering_test.h
+++ b/android_webview/browser/test/rendering_test.h
@@ -46,7 +46,7 @@ class RenderingTest : public testing::Test,
   void ParentDrawConstraintsUpdated(
       const ParentCompositorDrawConstraints& draw_constraints) override {}
   // WindowHooks overrides.
-  void WillOnDraw() override {}
+  void WillOnDraw() override;
   void DidOnDraw(bool success) override {}
   void WillSyncOnRT(SharedRendererState* functor) override {}
   void DidSyncOnRT(SharedRendererState* functor) override {}
@@ -67,6 +67,7 @@ class RenderingTest : public testing::Test,
   void InitializeCompositor();
   void Attach();
   void EndTest();
+  void SetCompositorFrame();
 
   scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner_;
   scoped_ptr<BrowserViewRenderer> browser_view_renderer_;