ui: Prevent DelegatedFrameHost from taking CompositorResizeLock forever

content/browser/renderer_host/render_widget_host_view_aura_unittest.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/renderer_host/render_widget_host_view_aura.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <tuple>
@@ skipping 2594 matching lines @@
 
   // When the frame of the correct size is committed, the CompositorResizeLock
   // is released.
   view_->RunOnCompositingDidCommit();
   EXPECT_FALSE(view_->resize_locked());
   EXPECT_FALSE(view_->compositor_locked());
 
   view_->window_->RemoveObserver(&observer);
 }
 
+// When the DelegatedFrameHost does not have a frame from the renderer, it has
+// no reason to lock the compositor as there can't be guttering around a
+// renderer frame that doesn't exist.
+TEST_F(RenderWidgetHostViewAuraTest, MissingFramesDontLock) {
+  gfx::Rect view_rect(100, 100);
+  gfx::Size frame_size = view_rect.size();
+
+  view_->InitAsChild(nullptr);
+  aura::client::ParentWindowWithContext(
+      view_->GetNativeView(), parent_view_->GetNativeView()->GetRootWindow(),
+      gfx::Rect());
+
+  // The view is resized before the first frame, which should not lock the
+  // compositor as it's never received a frame to show yet.
+  view_->SetSize(view_rect.size());
+
+  EXPECT_FALSE(view_->resize_locked());
+  EXPECT_FALSE(view_->compositor_locked());
+
+  // Submit a frame of initial size to make a frame present in
+  // DelegatedFrameHost, at which point locking becomes feasible if resized.
+  view_->SubmitCompositorFrame(
+      kArbitraryLocalSurfaceId,
+      MakeDelegatedFrame(1.f, frame_size, gfx::Rect(frame_size)));
+  view_->RunOnCompositingDidCommit();
+
+  EXPECT_FALSE(view_->resize_locked());
+  EXPECT_FALSE(view_->compositor_locked());
+
+  // The view is resized and has its frame evicted, before a new frame arrives.
+  // The resize will lock the compositor, but when evicted, it should no longer
+  // be locked.
+  view_rect.SetRect(0, 0, 150, 150);
+  view_->SetSize(view_rect.size());
+  EXPECT_TRUE(view_->resize_locked());
+  EXPECT_TRUE(view_->compositor_locked());
+
+  view_->ClearCompositorFrame();
+  EXPECT_FALSE(view_->resize_locked());
+  EXPECT_FALSE(view_->compositor_locked());
+
+  // And future resizes after eviction should not lock the compositor since
+  // there is no frame present.
+  view_rect.SetRect(0, 0, 120, 120);
+  view_->SetSize(view_rect.size());
+  EXPECT_FALSE(view_->resize_locked());
+  EXPECT_FALSE(view_->compositor_locked());
+}
+
 TEST_F(RenderWidgetHostViewAuraTest, OutputSurfaceIdChange) {
   gfx::Rect view_rect(100, 100);
   gfx::Size frame_size = view_rect.size();
 
   view_->InitAsChild(nullptr);
   aura::client::ParentWindowWithContext(
       view_->GetNativeView(),
       parent_view_->GetNativeView()->GetRootWindow(),
       gfx::Rect());
   view_->SetSize(view_rect.size());
@@ skipping 2818 matching lines @@
     // There is no composition in the beginning.
     EXPECT_FALSE(has_composition_text());
     SetHasCompositionTextToTrue();
     view->ImeCancelComposition();
     // The composition must have been canceled.
     EXPECT_FALSE(has_composition_text());
   }
 }
 
 }  // namespace content