Added UMA stat for tracking accidental navigations on double tap.

content/browser/android/content_view_core_impl.cc

Index: content/browser/android/content_view_core_impl.cc
diff --git a/content/browser/android/content_view_core_impl.cc b/content/browser/android/content_view_core_impl.cc
index c423adb26a525acca2f5cb89f0401acbcca22de2..83ce647aff88a4c2c853575cf3735dd14dba0e2e 100644
--- a/content/browser/android/content_view_core_impl.cc
+++ b/content/browser/android/content_view_core_impl.cc
@@ -11,6 +11,7 @@
 #include "base/command_line.h"
 #include "base/json/json_writer.h"
 #include "base/logging.h"
+#include "base/metrics/histogram.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/values.h"
 #include "cc/layers/layer.h"
@@ -1620,6 +1621,31 @@ void ContentViewCoreImpl::SetAccessibilityEnabled(JNIEnv* env, jobject obj,
   }
 }
 
+void ContentViewCoreImpl::SendSingleTapUma(JNIEnv* env,
+                                           jobject obj,
+                                           jint type,
+                                           jint count) {
+  UMA_HISTOGRAM_ENUMERATION("Event.SingleTapType", type, count);
+}
+
+void ContentViewCoreImpl::SendActionAfterDoubleTapUma(JNIEnv* env,
+                                                      jobject obj,
+                                                      jint type,
+                                                      jboolean has_delay,
+                                                      jint count) {
+  // This UMA stat tracks a user's action after a double tap within
+  // k seconds (where k == 5 currently). This UMA will tell us if
+  // removing the tap gesture delay will lead to significantly more
+  // accidental navigations after a double tap.
+  if (has_delay) {
+      UMA_HISTOGRAM_ENUMERATION("Event.ActionAfterDoubleTapWithDelay", type,
+          count);

[Alexei Svitkine (slow), 2013/11/05 22:18:18]

Nit: Align |count|, here and below.

+  } else {
+      UMA_HISTOGRAM_ENUMERATION("Event.ActionAfterDoubleTapNoDelay", type,
+          count);
+  }
+}
+
 void ContentViewCoreImpl::SendOrientationChangeEventInternal() {
   RenderWidgetHostViewAndroid* rwhv = GetRenderWidgetHostViewAndroid();
   if (rwhv)