Add latency measurement system

cc/gl_renderer_unittest.cc

Index: cc/gl_renderer_unittest.cc
diff --git a/cc/gl_renderer_unittest.cc b/cc/gl_renderer_unittest.cc
index 8521627ab2f385e397d9a9f0d129b5e59dfd6c8f..4e9ca8a89dd712bfcc964b37301e46ee8a46fa40 100644
--- a/cc/gl_renderer_unittest.cc
+++ b/cc/gl_renderer_unittest.cc
@@ -82,6 +82,7 @@ public:
     virtual void setManagedMemoryPolicy(const ManagedMemoryPolicy& policy) OVERRIDE { m_memoryAllocationLimitBytes = policy.bytesLimitWhenVisible; }
     virtual void enforceManagedMemoryPolicy(const ManagedMemoryPolicy& policy) OVERRIDE { if (m_lastCallWasSetVisibility) *m_lastCallWasSetVisibility = false; }
     virtual bool hasImplThread() const OVERRIDE { return false; }
+    virtual void onReceivedLatencyInfo(const WebKit::WebLatencyInfoImpl&) OVERRIDE { }
 
     // Methods added for test.
     int setFullRootLayerDamageCount() const { return m_setFullRootLayerDamageCount; }