Revert of Remove burst mode from VSyncMonitor. (https://codereview.ch…

…romium.org/346813002/)

Reason for revert:
Four of the introduced tests time out on Android.

VSyncMonitorTest#testVSyncActivationFromIdleAllowJBVSync
VSyncMonitorTest#testVSyncActivationFromIdleDisallowJBVSync
VSyncMonitorTest#testVSyncPeriodAllowJBVSync
VSyncMonitorTest#testVSyncPeriodDisallowJBVSync

The log output can be seen here:

http://build.chromium.org/p/chromium.linux/builders/Android%20Tests%20%28dbg%29/builds/21188/steps/contentshell_instrumentation_tests/logs/stdio

This failure could be observed in the try-bot results as part of the patch. Please do not use NOTRY unless you're absolutely certain that the failures are unrelated.

Original issue's description:
> Remove burst mode from VSyncMonitor.
> 
> Extra vsyncs after each rendering cause 1% more power consumption.
> 
> NOTRY=true
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=279997

TBR=tedchoc@chromium.org,sievers@chromium.org,aruslan@chromium.org,brianderson@chromium.org,skyostil@google.com,skyostil@chromium.org,bulach@chromium.org,miguelg@chromium.org,yfriedman@chromium.org,newt@chromium.org,egor.starkov@samsung.com
NOTREECHECKS=true
NOTRY=true

Review URL: https://codereview.chromium.org/358473006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@280012 0039d316-1c4b-4281-b951-d872f2087c98

AUTHORS

@@ -104,7 +104,6 @@ Douglas F. Turner <doug.turner@gmail.com>
 Eduardo Lima (Etrunko) <eduardo.lima@intel.com>
 Edward Crossman <tedoc2000@gmail.com>
 Eero Häkkinen <e.hakkinen@partner.samsung.com>
-Egor Starkov <egor.starkov@samsung.com>
 Ehsan Akhgari <ehsan.akhgari@gmail.com>
 Elan Ruusamäe <elan.ruusamae@gmail.com>
 Eric Ahn <byungwook.ahn@gmail.com>

content/public/android/javatests/src/org/chromium/content/browser/VSyncMonitorTest.java

@@ -82,7 +82,7 @@ public VSyncMonitor call() {
     private void performVSyncPeriodTest(boolean enableJBVSync) throws InterruptedException {
         // Collect roughly one second of data on a 60 fps display.
         collectAndCheckVSync(enableJBVSync, 60, true);
-        collectAndCheckVSync(enableJBVSync, 60, false);
+        collectAndCheckVSync(enableJBVSync, VSyncMonitor.MAX_AUTO_ONVSYNC_COUNT, false);
     }
 
     private void collectAndCheckVSync(

ui/android/java/src/org/chromium/ui/VSyncMonitor.java

@@ -15,6 +15,9 @@
 
 /**
  * Notifies clients of the default displays's vertical sync pulses.
+ * This class works in "burst" mode: once the update is requested, the listener will be
+ * called MAX_VSYNC_COUNT times on the vertical sync pulses (on JB) or on every refresh
+ * period (on ICS, see below), unless stop() is called.
  * On ICS, VSyncMonitor relies on setVSyncPointForICS() being called to set a reasonable
  * approximation of a vertical sync starting point; see also http://crbug.com/156397.
  */
@@ -23,6 +26,7 @@ public class VSyncMonitor {
     private static final long NANOSECONDS_PER_SECOND = 1000000000;
     private static final long NANOSECONDS_PER_MILLISECOND = 1000000;
     private static final long NANOSECONDS_PER_MICROSECOND = 1000;
+    public static final int MAX_AUTO_ONVSYNC_COUNT = 5;
 
     /**
      * VSync listener class
@@ -42,6 +46,7 @@ public interface Listener {
     private final long mRefreshPeriodNano;
 
     private boolean mHaveRequestInFlight;
+    private int mTriggerNextVSyncCount;
 
     // Choreographer is used to detect vsync on >= JB.
     private final Choreographer mChoreographer;
@@ -79,6 +84,7 @@ public VSyncMonitor(Context context, VSyncMonitor.Listener listener, boolean ena
                 .getDefaultDisplay().getRefreshRate();
         if (refreshRate <= 0) refreshRate = 60;
         mRefreshPeriodNano = (long) (NANOSECONDS_PER_SECOND / refreshRate);
+        mTriggerNextVSyncCount = 0;
 
         if (enableJBVSync && Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
             // Use Choreographer on JB+ to get notified of vsync.
@@ -139,13 +145,16 @@ private boolean isVSyncSignalAvailable() {
      * after this function is called.
      */
     public void stop() {
+        mTriggerNextVSyncCount = 0;
     }
 
     /**
      * Request to be notified of the closest display vsync events.
      * Listener.onVSync() will be called soon after the upcoming vsync pulses.
+     * It will be called at most MAX_AUTO_ONVSYNC_COUNT times unless requestUpdate() is called.
      */
     public void requestUpdate() {
+        mTriggerNextVSyncCount = MAX_AUTO_ONVSYNC_COUNT;
         postCallback();
     }
 
@@ -165,6 +174,10 @@ private void onVSyncCallback(long frameTimeNanos, long currentTimeNanos) {
         assert mHaveRequestInFlight;
         mHaveRequestInFlight = false;
         mLastVSyncCpuTimeNano = currentTimeNanos;
+        if (mTriggerNextVSyncCount >= 0) {
+            mTriggerNextVSyncCount--;
+            postCallback();
+        }
         if (mListener != null) {
             mListener.onVSync(this, frameTimeNanos / NANOSECONDS_PER_MICROSECOND);
         }