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..f0d9680ec757cd5686727ee7ba1b09eccef20961 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 +1621,34 @@ void ContentViewCoreImpl::SetAccessibilityEnabled(JNIEnv* env, jobject obj,
   }
 }
 
+void ContentViewCoreImpl::SendSingleTapUma(
+    JNIEnv* env,

[Alexei Svitkine (slow), 2013/11/02 00:12:39]

Nit: move this to the line above and align the other args, same for the function
below.

[bokan, 2013/11/04 20:01:08]

Done.

+    jobject obj,
+    int type,
+    int count) {
+  UMA_HISTOGRAM_ENUMERATION("Event.SingleTapType",
+    type, count);

[Alexei Svitkine (slow), 2013/11/02 00:12:39]

Nit: These can fit on the previous line.

[bokan, 2013/11/04 20:01:08]

Done.

+}
+
+void ContentViewCoreImpl::SendActionAfterDoubleTapUma(
+    JNIEnv* env,
+    jobject obj,
+    int type,
+    bool hasDelay,

[Alexei Svitkine (slow), 2013/11/02 00:12:39]

Nit: has_delay

[bokan, 2013/11/04 20:01:08]

Done.

+    int 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(hasDelay) {

[Alexei Svitkine (slow), 2013/11/02 00:12:39]

Nit: Space after if

[bokan, 2013/11/04 20:01:08]

Done.

+      UMA_HISTOGRAM_ENUMERATION("Event.ActionAfterDoubleTapWithDelay",
+        type, count);

[Alexei Svitkine (slow), 2013/11/02 00:12:39]

Nit: Can these fit on the previous line? If not, this needs to indent 2 more
(same for below).

[bokan, 2013/11/04 20:01:08]

Done.

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