Store the NSEvent.description in a crash key in -[BrowserCrApplication sendEvent:].

BUG=520706
R=erikchen@chromium.org

Review-Url: https://codereview.chromium.org/2545823002
Cr-Commit-Position: refs/heads/master@{#435630}

chrome/browser/chrome_browser_application_mac.mm

@@ -351,6 +351,9 @@ void CancelTerminate() {
 }
 
 - (void)sendEvent:(NSEvent*)event {
+  base::debug::ScopedCrashKey crash_key(
+      crash_keys::mac::kNSEvent, base::SysNSStringToUTF8([event description]));
+
   base::mac::CallWithEHFrame(^{
     switch (event.type) {
       case NSLeftMouseDown:

chrome/common/crash_keys.cc

@@ -82,6 +82,8 @@ const char kNSExceptionTrace[] = "nsexception_bt";
 
 const char kSendAction[] = "sendaction";
 
+const char kNSEvent[] = "nsevent";
+
 }  // namespace mac
 #endif
 
@@ -156,6 +158,7 @@ size_t RegisterChromeCrashKeys() {
     { mac::kNSException, kMediumSize },
     { mac::kNSExceptionTrace, kMediumSize },
     { mac::kSendAction, kMediumSize },
+    { mac::kNSEvent, kMediumSize },
     { mac::kZombie, kMediumSize },
     { mac::kZombieTrace, kMediumSize },
     // content/:

chrome/common/crash_keys.h

@@ -130,6 +130,9 @@ extern const char kNSExceptionTrace[];
 // target-action.
 extern const char kSendAction[];
 
+// In the CrApplication, records information about the current event.
+extern const char kNSEvent[];
+
 }  // namespace mac
 #endif