cc: Fix overwriting of commit completion event in MFBA mode.

cc/trees/layer_tree_host_unittest_proxy.cc

Index: cc/trees/layer_tree_host_unittest_proxy.cc
diff --git a/cc/trees/layer_tree_host_unittest_proxy.cc b/cc/trees/layer_tree_host_unittest_proxy.cc
index 46a2d36e7d7ffb57ea410d30fc68065e010e4ef9..d19ec46b6094c8b1aeed8c51f50aa76ff52b69ff 100644
--- a/cc/trees/layer_tree_host_unittest_proxy.cc
+++ b/cc/trees/layer_tree_host_unittest_proxy.cc
@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include "base/atomic_ref_count.h"
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "cc/test/fake_content_layer_client.h"
@@ -280,64 +281,152 @@ PROXY_MAIN_THREADED_TEST_F(ProxyMainThreadedSetNeedsCommitWhileAnimating);
 
 class ProxyMainThreadedCommitWaitsForActivation : public ProxyMainThreaded {
  protected:
-  ProxyMainThreadedCommitWaitsForActivation() : commits_completed_(0) {}
+  ProxyMainThreadedCommitWaitsForActivation()
+      : num_commits_(0), commit_blocked_on_activation_(0) {}
   ~ProxyMainThreadedCommitWaitsForActivation() override {}
 
   void BeginTest() override { proxy()->SetNeedsCommit(); }
 
+  void DidBeginMainFrame() override {
+    // Check that commit is not blocked on activation after it finishes on the
+    // impl thread.
+    bool commit_blocked_on_activation =
+        !base::AtomicRefCountIsZero(&commit_blocked_on_activation_);
+    EXPECT_FALSE(commit_blocked_on_activation);
+  }
+
   void ScheduledActionCommit() override {
-    switch (commits_completed_) {
+    switch (num_commits_) {
       case 0:
-        // The first commit does not wait for activation. Verify that the
-        // completion event is cleared.
-        EXPECT_FALSE(GetProxyImplForTest()->HasCommitCompletionEvent());
-        EXPECT_FALSE(GetProxyImplForTest()->GetNextCommitWaitsForActivation());
-
+        // The next commit is marked as blocked on activation.
+        EXPECT_TRUE(base::AtomicRefCountIsZero(&commit_blocked_on_activation_));
+        base::AtomicRefCountInc(&commit_blocked_on_activation_);
         // Set next commit waits for activation and start another commit.
-        commits_completed_++;
         PostNextCommitWaitsForActivationToMainThread();
+      // Fallthrough.
+      case 1:
         PostSetNeedsCommitToMainThread();
         break;
+    }
+    num_commits_++;
+  }
+
+  void DidActivateSyncTree() override {
+    switch (num_commits_) {
+      case 2:
+        // Mark commit as unblocked since activation is done.
+        EXPECT_TRUE(base::AtomicRefCountIsOne(&commit_blocked_on_activation_));
+        base::AtomicRefCountDec(&commit_blocked_on_activation_);
+        break;
+      case 3:
+        EndTest();
+        break;
+    }
+  }
+
+  void AfterTest() override {
+    // It is safe to read num_commits_ on the main thread now since AfterTest()
+    // runs after the LayerTreeHost is destroyed and the impl thread tear down
+    // is finished.
+    EXPECT_EQ(3, num_commits_);
+  }
+
+ private:
+  int num_commits_;
+  base::AtomicRefCount commit_blocked_on_activation_;
+
+  DISALLOW_COPY_AND_ASSIGN(ProxyMainThreadedCommitWaitsForActivation);
+};
+
+PROXY_MAIN_THREADED_TEST_F(ProxyMainThreadedCommitWaitsForActivation);
+
+// Test for a corner case of main frame before activation (MFBA) and commit
+// waits for activation. If a commit (with wait for activation flag set)
+// is ready before the activation for a previous commit then the activation
+// should not signal the completion event of the second commit.
+class ProxyMainThreadedCommitWaitsForActivationMFBA : public ProxyMainThreaded {
+ protected:
+  ProxyMainThreadedCommitWaitsForActivationMFBA()
+      : num_commits_(0), commit_blocked_on_activation_(0) {}
+  ~ProxyMainThreadedCommitWaitsForActivationMFBA() override {}
+
+  void InitializeSettings(LayerTreeSettings* settings) override {
+    settings->main_frame_before_activation_enabled = true;
+    ProxyMainThreaded::InitializeSettings(settings);
+  }
+
+  void BeginTest() override { proxy()->SetNeedsCommit(); }
+
+  void DidBeginMainFrame() override {
+    // Check that commit is not blocked on activation after it finishes on the
+    // impl thread.
+    bool commit_blocked_on_activation =
+        !base::AtomicRefCountIsZero(&commit_blocked_on_activation_);
+    EXPECT_FALSE(commit_blocked_on_activation);
+  }
+
+  void StartCommitOnImpl() override {
+    switch (num_commits_) {
+      case 0:
+        // Block activation until next commit is ready.
+        GetProxyImplForTest()->BlockNotifyReadyToActivateForTesting(true);
+        break;
       case 1:
-        // The second commit should be held until activation.
-        EXPECT_TRUE(GetProxyImplForTest()->HasCommitCompletionEvent());
-        EXPECT_TRUE(GetProxyImplForTest()->GetNextCommitWaitsForActivation());
+        // After the second commit is ready unblock activation.
+        if (num_commits_ == 1) {
+          ImplThreadTaskRunner()->PostTask(
+              FROM_HERE,
+              base::Bind(
+                  &ProxyImplForTest::BlockNotifyReadyToActivateForTesting,
+                  base::Unretained(GetProxyImplForTest()), false));
+        }
+        break;
+    }
+  }
 
-        // Start another commit to verify that this is not held until
-        // activation.
-        commits_completed_++;
+  void ScheduledActionCommit() override {
+    switch (num_commits_) {
+      case 0:
+        // The next commit is marked as blocked on activation.
+        EXPECT_TRUE(base::AtomicRefCountIsZero(&commit_blocked_on_activation_));
+        base::AtomicRefCountInc(&commit_blocked_on_activation_);
+        // Set next commit waits for activation and start another commit.
+        PostNextCommitWaitsForActivationToMainThread();
+      // Fallthrough.
+      case 1:
         PostSetNeedsCommitToMainThread();
         break;
-      case 2:
-        // The third commit should not wait for activation.
-        EXPECT_FALSE(GetProxyImplForTest()->HasCommitCompletionEvent());
-        EXPECT_FALSE(GetProxyImplForTest()->GetNextCommitWaitsForActivation());
-
-        commits_completed_++;
     }
+    num_commits_++;
   }
 
   void DidActivateSyncTree() override {
-    // The next_commit_waits_for_activation should have been cleared after the
-    // sync tree is activated.
-    EXPECT_FALSE(GetProxyImplForTest()->GetNextCommitWaitsForActivation());
-    if (commits_completed_ == 3)
-      EndTest();
+    switch (num_commits_) {
+      case 2:
+        // Mark commit as unblocked since activation is done.
+        EXPECT_TRUE(base::AtomicRefCountIsOne(&commit_blocked_on_activation_));
+        base::AtomicRefCountDec(&commit_blocked_on_activation_);
+        break;
+      case 3:
+        EndTest();
+        break;
+    }
   }
 
   void AfterTest() override {
-    // It is safe to read commits_completed_ on the main thread now since
-    // AfterTest() runs after the LayerTreeHost is destroyed and the impl thread
-    // tear down is finished.
-    EXPECT_EQ(3, commits_completed_);
+    // It is safe to read num_commits_ on the main thread now since AfterTest()
+    // runs after the LayerTreeHost is destroyed and the impl thread tear down
+    // is finished.
+    EXPECT_EQ(3, num_commits_);
   }
 
  private:
-  int commits_completed_;
+  int num_commits_;
+  base::AtomicRefCount commit_blocked_on_activation_;
 
-  DISALLOW_COPY_AND_ASSIGN(ProxyMainThreadedCommitWaitsForActivation);
+  DISALLOW_COPY_AND_ASSIGN(ProxyMainThreadedCommitWaitsForActivationMFBA);
 };
 
-PROXY_MAIN_THREADED_TEST_F(ProxyMainThreadedCommitWaitsForActivation);
+PROXY_MAIN_THREADED_TEST_F(ProxyMainThreadedCommitWaitsForActivationMFBA);
 
 }  // namespace cc