Upstream MemoryUma and use it for all activities.

chrome/android/java/src/org/chromium/chrome/browser/init/AsyncInitializationActivity.java

Index: chrome/android/java/src/org/chromium/chrome/browser/init/AsyncInitializationActivity.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/init/AsyncInitializationActivity.java b/chrome/android/java/src/org/chromium/chrome/browser/init/AsyncInitializationActivity.java
index 1e94673e032b188b7a5e6d7d682a0842965330cf..d7927eda8e5795ed7cbc1334ff334d4cf09ec464 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/init/AsyncInitializationActivity.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/init/AsyncInitializationActivity.java
@@ -15,6 +15,8 @@ import android.view.View;
 import android.view.ViewTreeObserver;
 import android.view.ViewTreeObserver.OnPreDrawListener;
 
+import org.chromium.chrome.browser.metrics.MemoryUma;
+
 /**
  * An activity that talks with application and activity level delegates for async initialization.
  */
@@ -30,6 +32,7 @@ public abstract class AsyncInitializationActivity extends ActionBarActivity impl
     private Bundle mSavedInstanceState;
     private boolean mDestroyed;
     private NativeInitializationController mNativeInitializationController;
+    private MemoryUma mMemoryUma;
 
     public AsyncInitializationActivity() {
         mHandler = new Handler();
@@ -71,6 +74,7 @@ public abstract class AsyncInitializationActivity extends ActionBarActivity impl
 
     @Override
     public void finishNativeInitialization() {
+        mMemoryUma = new MemoryUma();
         mNativeInitializationController.onNativeInitializationComplete();
     }
 
@@ -146,6 +150,7 @@ public abstract class AsyncInitializationActivity extends ActionBarActivity impl
     @Override
     public void onStop() {
         super.onStop();
+        if (mMemoryUma != null) mMemoryUma.onStop();
         mNativeInitializationController.onStop();
     }
 
@@ -196,6 +201,19 @@ public abstract class AsyncInitializationActivity extends ActionBarActivity impl
         return false;
     }
 
+    @Override
+    public void onLowMemory() {
+        super.onLowMemory();
+        if (mMemoryUma != null) mMemoryUma.onLowMemory();
+    }
+
+    @Override
+    public void onTrimMemory(int level) {
+        super.onTrimMemory(level);
+        if (mMemoryUma != null) mMemoryUma.onTrimMemory(level);
+    }
+
+
     /**
      * Extending classes should implement this and call {@link Activity#setContentView(int)} in it.
      */