Add UMA histogram for whether page loads are mobile optimized

content/public/android/java/src/org/chromium/content/browser/ContentViewCore.java

Index: content/public/android/java/src/org/chromium/content/browser/ContentViewCore.java
diff --git a/content/public/android/java/src/org/chromium/content/browser/ContentViewCore.java b/content/public/android/java/src/org/chromium/content/browser/ContentViewCore.java
index 1616b717f64c62e4414f0d72f5207db76c7e3fb3..7a54122c2f5686c2c36c3ed526a400b285b72340 100644
--- a/content/public/android/java/src/org/chromium/content/browser/ContentViewCore.java
+++ b/content/public/android/java/src/org/chromium/content/browser/ContentViewCore.java
@@ -56,6 +56,7 @@ import org.chromium.base.ObserverList;
 import org.chromium.base.ObserverList.RewindableIterator;
 import org.chromium.base.TraceEvent;
 import org.chromium.base.VisibleForTesting;
+import org.chromium.base.metrics.RecordHistogram;
 import org.chromium.content.R;
 import org.chromium.content.browser.ScreenOrientationListener.ScreenOrientationObserver;
 import org.chromium.content.browser.accessibility.AccessibilityInjector;
@@ -766,6 +767,14 @@ public class ContentViewCore
             }
 
             @Override
+            public void didFinishLoad(long frameId, String validatedUrl, boolean isMainFrame) {
+                if (isMainFrame) {

[jdduke (slow), 2015/02/19 23:39:59]

I wonder about the timing of this call relative to frame metadata receipt... I
would hope this always arrives after the frame metadata corresponding to the
initial frame, just want to make sure we're not racing.

+                    RecordHistogram.recordBooleanHistogram(
+                            "Navigation.MobileOptimized", getIsMobileOptimizedHint());
+                }
+            }
+
+            @Override
             public void renderProcessGone(boolean wasOomProtected) {
                 hidePopupsAndClearSelection();
                 resetScrollInProgress();