Revert 175275

cc/frame_rate_controller.cc

Index: cc/frame_rate_controller.cc
===================================================================
--- cc/frame_rate_controller.cc	(revision 175415)
+++ cc/frame_rate_controller.cc	(working copy)
@@ -10,6 +10,14 @@
 #include "cc/time_source.h"
 #include "cc/thread.h"
 
+namespace {
+
+// This will be the maximum number of pending frames unless
+// FrameRateController::setMaxFramesPending is called.
+const int defaultMaxFramesPending = 2;
+
+}  // namespace
+
 namespace cc {
 
 class FrameRateControllerTimeSourceAdapter : public TimeSourceClient {
@@ -33,7 +41,7 @@
 FrameRateController::FrameRateController(scoped_refptr<TimeSource> timer)
     : m_client(0)
     , m_numFramesPending(0)
-    , m_maxFramesPending(0)
+    , m_maxFramesPending(defaultMaxFramesPending)
     , m_timeSource(timer)
     , m_active(false)
     , m_swapBuffersCompleteSupported(true)
@@ -48,7 +56,7 @@
 FrameRateController::FrameRateController(Thread* thread)
     : m_client(0)
     , m_numFramesPending(0)
-    , m_maxFramesPending(0)
+    , m_maxFramesPending(defaultMaxFramesPending)
     , m_active(false)
     , m_swapBuffersCompleteSupported(true)
     , m_isTimeSourceThrottling(false)
@@ -82,7 +90,7 @@
 
 void FrameRateController::setMaxFramesPending(int maxFramesPending)
 {
-    DCHECK(maxFramesPending >= 0);
+    DCHECK(maxFramesPending > 0);
     m_maxFramesPending = maxFramesPending;
 }
 
@@ -102,13 +110,13 @@
     DCHECK(m_active);
 
     // Check if we have too many frames in flight.
-    bool throttled = m_maxFramesPending && m_numFramesPending >= m_maxFramesPending;
+    bool throttled = m_numFramesPending >= m_maxFramesPending;
     TRACE_COUNTER_ID1("cc", "ThrottledVSyncInterval", m_thread, throttled);
 
     if (m_client)
         m_client->vsyncTick(throttled);
 
-    if (m_swapBuffersCompleteSupported && !m_isTimeSourceThrottling && !throttled)
+    if (m_swapBuffersCompleteSupported && !m_isTimeSourceThrottling && m_numFramesPending < m_maxFramesPending)
         postManualTick();
 }