cc: Adding BeginFrameTracker object and removing Now() from LTHI.

cc/trees/layer_tree_host_unittest_context.cc

Index: cc/trees/layer_tree_host_unittest_context.cc
diff --git a/cc/trees/layer_tree_host_unittest_context.cc b/cc/trees/layer_tree_host_unittest_context.cc
index 8b09054894341ee5995163ffbd2d9d39c481c9c7..4b5b9f55224e4c4901dfb0db6a6d4b844f3b6f5d 100644
--- a/cc/trees/layer_tree_host_unittest_context.cc
+++ b/cc/trees/layer_tree_host_unittest_context.cc
@@ -393,8 +393,8 @@ class MultipleCompositeDoesNotCreateOutputSurface
   }
 
   void BeginTest() override {
-    layer_tree_host()->Composite(base::TimeTicks());
-    layer_tree_host()->Composite(base::TimeTicks());
+    layer_tree_host()->Composite(base::TimeTicks::FromInternalValue(1));
+    layer_tree_host()->Composite(base::TimeTicks::FromInternalValue(2));
   }
 
   scoped_ptr<OutputSurface> CreateOutputSurface() override {
@@ -439,12 +439,12 @@ class FailedCreateDoesNotCreateExtraOutputSurface
 
   void BeginTest() override {
     // First composite tries to create a surface.
-    layer_tree_host()->Composite(base::TimeTicks());
+    layer_tree_host()->Composite(base::TimeTicks::FromInternalValue(1));
     EXPECT_EQ(num_requests_, 2);
     EXPECT_TRUE(has_failed_);
 
     // Second composite should not request or fail.
-    layer_tree_host()->Composite(base::TimeTicks());
+    layer_tree_host()->Composite(base::TimeTicks::FromInternalValue(2));
     EXPECT_EQ(num_requests_, 2);
     EndTest();
   }
@@ -489,7 +489,9 @@ class LayerTreeHostContextTestCommitAfterDelayedOutputSurface
         LayerTreeHostContextTest::CreateOutputSurface());
   }
 
-  void BeginTest() override { layer_tree_host()->Composite(base::TimeTicks()); }
+  void BeginTest() override {
+    layer_tree_host()->Composite(base::TimeTicks::FromInternalValue(1));
+  }
 
   void ScheduleComposite() override {
     if (creating_output_)
@@ -522,7 +524,7 @@ class LayerTreeHostContextTestAvoidUnnecessaryComposite
 
   void BeginTest() override {
     in_composite_ = true;
-    layer_tree_host()->Composite(base::TimeTicks());
+    layer_tree_host()->Composite(base::TimeTicks::FromInternalValue(1));
     in_composite_ = false;
   }