Fix LayerTreeHostCacheBehaviorOnOutputSurfaceRecreated test

LayerTreeHostCacheBehaviorOnOutputSurfaceRecreated test was incorrectly
relying on WillBeginImplFrameOnThread only being called once after the
OutputSurface was recreated. In reality, this function could be called
multiple times.

This patch causes us to handle cleanup in DidInitializeOutputSurface,
which will only be called once after recreating an OutputSurface.

BUG=642881,642836
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_precise_blink_rel

Review-Url: https://codereview.chromium.org/2297413002
Cr-Commit-Position: refs/heads/master@{#415791}

cc/trees/layer_tree_host_unittest.cc

@@ -576,27 +576,38 @@ class LayerTreeHostCacheBehaviorOnOutputSurfaceRecreated
  public:
   void WillBeginImplFrameOnThread(LayerTreeHostImpl* host_impl,
                                   const BeginFrameArgs& args) override {
+    // This code is run once, to trigger recreation of our OutputSurface.
+    if (has_recreated_)
+      return;
+
     // Ensure that our initialization expectations have completed.
     Mock::VerifyAndClearExpectations(mock_main_context_support_);
     Mock::VerifyAndClearExpectations(mock_worker_context_support_);
 
-    if (has_recreated_) {
-      // Destruction exptectations.
-      EXPECT_CALL(*mock_worker_context_support_,
-                  SetAggressivelyFreeResources(true));
-      EXPECT_CALL(*mock_main_context_support_,
-                  SetAggressivelyFreeResources(true));
-      EndTest();
-      return;
-    }
-    has_recreated_ = true;
-
     // Output surface lost expectations.
     EXPECT_CALL(*mock_worker_context_support_,
                 SetAggressivelyFreeResources(true));
     EXPECT_CALL(*mock_main_context_support_,
                 SetAggressivelyFreeResources(true));
     host_impl->DidLoseOutputSurface();
+    has_recreated_ = true;
+  }
+
+  void DidInitializeOutputSurface() override {
+    // This is run after we have recreated our OutputSurface.
+    if (!has_recreated_)
+      return;
+
+    // Ensure that our initialization expectations have completed.
+    Mock::VerifyAndClearExpectations(mock_main_context_support_);
+    Mock::VerifyAndClearExpectations(mock_worker_context_support_);
+
+    // Destruction exptectations.
+    EXPECT_CALL(*mock_worker_context_support_,
+                SetAggressivelyFreeResources(true));
+    EXPECT_CALL(*mock_main_context_support_,
+                SetAggressivelyFreeResources(true));
+    EndTest();
   }
 
  private: