Reland of Android: support multiple displays on C++ side

ui/android/java/src/org/chromium/ui/base/WindowAndroid.java

Index: ui/android/java/src/org/chromium/ui/base/WindowAndroid.java
diff --git a/ui/android/java/src/org/chromium/ui/base/WindowAndroid.java b/ui/android/java/src/org/chromium/ui/base/WindowAndroid.java
index 30fb1386d573875a4559b6026480020d667f469e..745c655ccc97387a9b531906e1ee8631bcaef6e7 100644
--- a/ui/android/java/src/org/chromium/ui/base/WindowAndroid.java
+++ b/ui/android/java/src/org/chromium/ui/base/WindowAndroid.java
@@ -181,8 +181,9 @@ public class WindowAndroid {
     }
 
     @CalledByNative
-    private static WindowAndroid createForTesting(Context context) {
-        return new WindowAndroid(context);
+    private static long createForTesting(Context context) {
+        WindowAndroid windowAndroid = new WindowAndroid(context);

[boliu, 2016/11/01 17:11:04]

maybe add a comment that java windowAndroid is owned by native, so is not
immediately eligible for gc here

[Tima Vaisburd, 2016/11/01 23:04:36]

Done.

+        return windowAndroid.getNativePointer();
     }
 
     @CalledByNative
@@ -533,7 +534,7 @@ public class WindowAndroid {
      */
     public long getNativePointer() {
         if (mNativeWindowAndroid == 0) {
-            mNativeWindowAndroid = nativeInit();
+            mNativeWindowAndroid = nativeInit(mDisplayAndroid.getSdkDisplayId());
         }
         return mNativeWindowAndroid;
     }
@@ -675,7 +676,11 @@ public class WindowAndroid {
         }
     }
 
-    private native long nativeInit();
+    /*
+     * The properties of DisplayAndroid used by native side.

[boliu, 2016/11/01 17:11:04]

hmm?

comment seems out of place

[Tima Vaisburd, 2016/11/01 23:04:36]

Forgot to delete it on prior cleanup. Removed.

+     */
+
+    private native long nativeInit(int displayId);
     private native void nativeOnVSync(long nativeWindowAndroid,
                                       long vsyncTimeMicros,
                                       long vsyncPeriodMicros);