[Background Sync] Use GcmNetworkManager to start the browser for sync events.

chrome/android/java/proguard.flags

Index: chrome/android/java/proguard.flags
diff --git a/chrome/android/java/proguard.flags b/chrome/android/java/proguard.flags
index 42f25bd386af3b142244f0e99a7e320106a44153..17a8e8ba0e36cc4f4a0943f73c5c796b06a4ff4c 100644
--- a/chrome/android/java/proguard.flags
+++ b/chrome/android/java/proguard.flags
@@ -113,6 +113,10 @@
   *;
 }
 
+-keepnames class com.google.android.gms.gcm.** {

[Yaron, 2015/10/19 20:34:36]

How many methods does this add? You can use this tool to check:
https://github.com/mihaip/dex-method-counts

[iclelland, 2015/10/20 18:56:05]

According to that tool, there are 137 methods included in the APK, under
com.google.android.gms.gcm, but only 27 of those are newly added.

With this CL, I see 45347 total methods in ChromePublicApk, including 137 under
c.g.a.gms.gcm.
Without it, I see 45323 methods, including 110 under c.g.a.gms.gcm.

+  *;
+}
+
 -keepnames class jp.tomorrowkey.android.gifplayer.** {
   public *;
 }