Don't let unittests access LTH from the impl thread.

This causes racy sadness.

BUG=235188

Review URL: https://codereview.chromium.org/1020803002

Cr-Commit-Position: refs/heads/master@{#321398}

cc/test/layer_tree_test.cc

@@ -878,4 +878,13 @@ void LayerTreeTest::DestroyLayerTreeHost() {
   layer_tree_host_ = nullptr;
 }
 
+LayerTreeHost* LayerTreeTest::layer_tree_host() {
+  // We check for a null proxy here as we sometimes ask for the layer tree host
+  // when the proxy does not exist, often for checking settings after a test has
+  // completed. For example, LTHPixelResourceTest::RunPixelResourceTest. See
+  // elsewhere in this file for other examples.
+  DCHECK(!proxy() || proxy()->IsMainThread() || proxy()->IsMainThreadBlocked());
+  return layer_tree_host_.get();
+}
+
 }  // namespace cc

cc/test/layer_tree_test.h

@@ -198,7 +198,7 @@ class LayerTreeTest : public testing::Test, public TestHooks {
 
   bool TestEnded() const { return ended_; }
 
-  LayerTreeHost* layer_tree_host() { return layer_tree_host_.get(); }
+  LayerTreeHost* layer_tree_host();
   bool delegating_renderer() const { return delegating_renderer_; }
   FakeOutputSurface* output_surface() { return output_surface_; }
   int LastCommittedSourceFrameNumber(LayerTreeHostImpl* impl) const;

cc/trees/layer_tree_host_unittest.cc

@@ -70,7 +70,17 @@ using testing::Mock;
 namespace cc {
 namespace {
 
-class LayerTreeHostTest : public LayerTreeTest {};
+class LayerTreeHostTest : public LayerTreeTest {
+ public:
+  LayerTreeHostTest() : contents_texture_manager_(nullptr) {}
+
+  void DidInitializeOutputSurface() override {
+    contents_texture_manager_ = layer_tree_host()->contents_texture_manager();
+  }
+
+ protected:
+  PrioritizedResourceManager* contents_texture_manager_;
+};
 
 // Test if the LTHI receives ReadyToActivate notifications from the TileManager
 // when no raster tasks get scheduled.
@@ -1463,7 +1473,7 @@ class LayerTreeHostTestDirectRendererAtomicCommit : public LayerTreeHostTest {
   }
 
   void DidActivateTreeOnThread(LayerTreeHostImpl* impl) override {
-    ASSERT_EQ(0u, layer_tree_host()->settings().max_partial_texture_updates);
+    ASSERT_EQ(0u, impl->settings().max_partial_texture_updates);
 
     TestWebGraphicsContext3D* context = TestContext();
 
@@ -1542,7 +1552,7 @@ class LayerTreeHostTestDelegatingRendererAtomicCommit
     : public LayerTreeHostTestDirectRendererAtomicCommit {
  public:
   void DidActivateTreeOnThread(LayerTreeHostImpl* impl) override {
-    ASSERT_EQ(0u, layer_tree_host()->settings().max_partial_texture_updates);
+    ASSERT_EQ(0u, impl->settings().max_partial_texture_updates);
 
     TestWebGraphicsContext3D* context = TestContext();
 
@@ -1659,7 +1669,7 @@ class LayerTreeHostTestAtomicCommitWithPartialUpdate
   }
 
   void CommitCompleteOnThread(LayerTreeHostImpl* impl) override {
-    ASSERT_EQ(1u, layer_tree_host()->settings().max_partial_texture_updates);
+    ASSERT_EQ(1u, impl->settings().max_partial_texture_updates);
 
     TestWebGraphicsContext3D* context = TestContext();
 
@@ -2383,12 +2393,10 @@ class LayerTreeHostTestShutdownWithOnlySomeResourcesEvicted
                                bool visible) override {
     if (visible) {
       // One backing should remain unevicted.
-      EXPECT_EQ(
-          100u * 100u * 4u * 1u,
-          layer_tree_host()->contents_texture_manager()->MemoryUseBytes());
+      EXPECT_EQ(100u * 100u * 4u * 1u,
+                contents_texture_manager_->MemoryUseBytes());
     } else {
-      EXPECT_EQ(
-          0u, layer_tree_host()->contents_texture_manager()->MemoryUseBytes());
+      EXPECT_EQ(0u, contents_texture_manager_->MemoryUseBytes());
     }
 
     // Make sure that contents textures are marked as having been
@@ -2403,9 +2411,9 @@ class LayerTreeHostTestShutdownWithOnlySomeResourcesEvicted
     switch (num_commits_) {
       case 1:
         // All three backings should have memory.
-        EXPECT_EQ(
-            100u * 100u * 4u * 3u,
-            layer_tree_host()->contents_texture_manager()->MemoryUseBytes());
+        EXPECT_EQ(100u * 100u * 4u * 3u,
+                  contents_texture_manager_->MemoryUseBytes());
+
         // Set a new policy that will kick out 1 of the 3 resources.
         // Because a resource was evicted, a commit will be kicked off.
         host_impl->SetMemoryPolicy(
@@ -2415,9 +2423,8 @@ class LayerTreeHostTestShutdownWithOnlySomeResourcesEvicted
         break;
       case 2:
         // Only two backings should have memory.
-        EXPECT_EQ(
-            100u * 100u * 4u * 2u,
-            layer_tree_host()->contents_texture_manager()->MemoryUseBytes());
+        EXPECT_EQ(100u * 100u * 4u * 2u,
+                  contents_texture_manager_->MemoryUseBytes());
         // Become backgrounded, which will cause 1 more resource to be
         // evicted.
         PostSetVisibleToMainThread(false);
@@ -3246,12 +3253,12 @@ class LayerTreeHostTestUIResource : public LayerTreeHostTest {
   }
 
   void CommitCompleteOnThread(LayerTreeHostImpl* impl) override {
-    if (!layer_tree_host()->settings().impl_side_painting)
+    if (!impl->settings().impl_side_painting)
       PerformTest(impl);
   }
 
   void DidActivateTreeOnThread(LayerTreeHostImpl* impl) override {
-    if (layer_tree_host()->settings().impl_side_painting)
+    if (impl->settings().impl_side_painting)
       PerformTest(impl);
   }
 

cc/trees/layer_tree_host_unittest_context.cc

@@ -110,7 +110,7 @@ class LayerTreeHostContextTest : public LayerTreeTest {
       // Only valid for single-threaded impl-side painting, which activates
       // immediately and will try to draw again when content has finished.
       DCHECK(!host_impl->proxy()->HasImplThread());
-      DCHECK(layer_tree_host()->settings().impl_side_painting);
+      DCHECK(host_impl->settings().impl_side_painting);
       return draw_result;
     }
     EXPECT_EQ(DRAW_SUCCESS, draw_result);
@@ -883,7 +883,7 @@ class LayerTreeHostContextTestLayersNotified : public LayerTreeHostContextTest {
     FakeContentLayerImpl* child_content = NULL;
     FakeContentLayerImpl* grandchild_content = NULL;
 
-    if (layer_tree_host()->settings().impl_side_painting) {
+    if (host_impl->settings().impl_side_painting) {
       root_picture = static_cast<FakePictureLayerImpl*>(
           host_impl->active_tree()->root_layer());
       child_picture =
@@ -903,7 +903,7 @@ class LayerTreeHostContextTestLayersNotified : public LayerTreeHostContextTest {
     ++num_commits_;
     switch (num_commits_) {
       case 1:
-        if (layer_tree_host()->settings().impl_side_painting) {
+        if (host_impl->settings().impl_side_painting) {
           EXPECT_EQ(0u, root_picture->release_resources_count());
           EXPECT_EQ(0u, child_picture->release_resources_count());
           EXPECT_EQ(0u, grandchild_picture->release_resources_count());
@@ -918,7 +918,7 @@ class LayerTreeHostContextTestLayersNotified : public LayerTreeHostContextTest {
         times_to_fail_create_ = 1;
         break;
       case 2:
-        if (layer_tree_host()->settings().impl_side_painting) {
+        if (host_impl->settings().impl_side_painting) {
           EXPECT_TRUE(root_picture->release_resources_count());
           EXPECT_TRUE(child_picture->release_resources_count());
           EXPECT_TRUE(grandchild_picture->release_resources_count());
@@ -1327,7 +1327,7 @@ class UIResourceLostTestSimple : public UIResourceLostTest {
   virtual void StepCompleteOnImplThread(LayerTreeHostImpl* impl) = 0;
 
   void CommitCompleteOnThread(LayerTreeHostImpl* impl) override {
-    if (!layer_tree_host()->settings().impl_side_painting) {
+    if (!impl->settings().impl_side_painting) {
       StepCompleteOnImplThread(impl);
       PostStepCompleteToMainThread();
       ++time_step_;
@@ -1335,7 +1335,7 @@ class UIResourceLostTestSimple : public UIResourceLostTest {
   }
 
   void DidActivateTreeOnThread(LayerTreeHostImpl* impl) override {
-    if (layer_tree_host()->settings().impl_side_painting) {
+    if (impl->settings().impl_side_painting) {
       StepCompleteOnImplThread(impl);
       PostStepCompleteToMainThread();
       ++time_step_;