Stricter user gestures for touch - measure and warn

third_party/WebKit/Source/platform/UserGestureIndicator.h

Index: third_party/WebKit/Source/platform/UserGestureIndicator.h
diff --git a/third_party/WebKit/Source/platform/UserGestureIndicator.h b/third_party/WebKit/Source/platform/UserGestureIndicator.h
index aa945209ad1bf09762b260d803bafa27fd754e67..11b14183708dcc6c2fa0f69f4f520f4e102daf95 100644
--- a/third_party/WebKit/Source/platform/UserGestureIndicator.h
+++ b/third_party/WebKit/Source/platform/UserGestureIndicator.h
@@ -51,18 +51,51 @@ public:
     virtual void setPauseInDebugger() = 0;
 };
 
+// Callback to be invoked when the state of a UserGestureIndicator is
+// first tested (only during the scope of a UserGestureIndiactor, does
+// not flow with the UserGestureToken).  It's the responsibility of the
+// caller to ensure the UserGestureUsedCallback is kept alive as long
+// as the UserGestureIndicator it's used in.
+// Note that this doesn't currently track EVERY way in which the
+// state of a UserGesture can be used (sometimes it's just propagated
+// elsewhere), but should include most use cases.  Therefore this is
+// suitable mainly for diagnostics and measurement purposes.
+class PLATFORM_EXPORT UserGestureUsedCallback {
+    WTF_MAKE_NONCOPYABLE(UserGestureUsedCallback);
+public:
+    UserGestureUsedCallback() { }
+    virtual ~UserGestureUsedCallback() { }
+    virtual void userGestureUsed() = 0;
+};
+
 class PLATFORM_EXPORT UserGestureIndicator final {
     USING_FAST_MALLOC(UserGestureIndicator);
     WTF_MAKE_NONCOPYABLE(UserGestureIndicator);
 public:
+    // Returns whether a user gesture is currently in progress.
+    // If true, invokes (and then clears) any UserGestureUsedCallback.
     static bool processingUserGesture();
+
+    // Returns whether a user gesture is currently in progress.
+    // Does not invoke the UserGestureQueriedCallback.
+    static bool processingUserGestureUntracked();
+
+    // Mark the current user gesture (if any) as having been used, such that
+    // it cannot be used again.  This is done only for very security-sensitive
+    // operations like creating a new process.
+    // Like processingUserGesture, may invoke/clear any UserGestureUsedCallback.
     static bool consumeUserGesture();
+
     static UserGestureToken* currentToken();
+
+    // Reset the notion of "since load".
     static void clearProcessedUserGestureSinceLoad();
+
+    // Returns whether a user gesture has occurred since page load.
     static bool processedUserGestureSinceLoad();
 
-    explicit UserGestureIndicator(ProcessingUserGestureState);
-    explicit UserGestureIndicator(PassRefPtr<UserGestureToken>);
+    explicit UserGestureIndicator(ProcessingUserGestureState, UserGestureUsedCallback* usageCallback = 0);
+    explicit UserGestureIndicator(PassRefPtr<UserGestureToken>, UserGestureUsedCallback* usageCallback = 0);
     ~UserGestureIndicator();
 
 private:
@@ -71,6 +104,7 @@ private:
     static bool s_processedUserGestureSinceLoad;
     ProcessingUserGestureState m_previousState;
     RefPtr<UserGestureToken> m_token;
+    UserGestureUsedCallback* m_usageCallback;
 };
 
 } // namespace blink