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..caa6cdb34a2b177b85652f471ce4bfc5813c0c32 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 +1621,35 @@ void ContentViewCoreImpl::SetAccessibilityEnabled(JNIEnv* env, jobject obj,
   }
 }
 
+void ContentViewCoreImpl::SendSingleTapUma(
+    JNIEnv* env,
+    jobject obj,
+    int type,
+    int count) {
+  UMA_HISTOGRAM_ENUMERATION("UserInput.SingleTapType",

[Rick Byers, 2013/11/01 19:27:03]

Nit: rather than create a new UserInput top level, it's probably nicer to re-use
either 'Touchscreen' or 'Event'.

[bokan, 2013/11/01 19:54:02]

Changed these to Event - Touchscreen doesn't seem to exist in histogram.xml

[Rick Byers, 2013/11/01 20:03:27]

Ah, this is another one that's still stuck in the old google-internal
histograms.xml file
(https://chromegw/viewvc/chrome-internal/trunk/tools/histograms/histograms.xml...).
 It should probably get moved to the public one.  You can go ahead and use it if
you like (does seem a little more appropriate than Event I think).  Eg. see
usage of it here:
https://code.google.com/p/chromium/codesearch#chromium/src/chrome/browser/met...

+    type, count);
+}
+
+void ContentViewCoreImpl::SendActionAfterDoubleTapUma(
+    JNIEnv* env,
+    jobject obj,
+    int type,
+    bool hasDelay,
+    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) {
+      UMA_HISTOGRAM_ENUMERATION("UserInput.ActionAfterDoubleTapWithDelay",
+        type, count);
+  } else {
+      UMA_HISTOGRAM_ENUMERATION("UserInput.ActionAfterDoubleTapNoDelay",
+        type, count);
+  }
+
+}
+
 void ContentViewCoreImpl::SendOrientationChangeEventInternal() {
   RenderWidgetHostViewAndroid* rwhv = GetRenderWidgetHostViewAndroid();
   if (rwhv)