[Debugging] Add instrumentation in TouchActionFilter

From the stack trace of the current crash report, we are not able to
tell the gesture sequence, which makes it hard to debug.

This CL adds a CrashKeyString in TouchActionFilter, and push necessary
events into that string. When it crashes, we should be able to retrieve
the gesture sequence from that crash key.

Bug: 869375
Change-Id: Ieb7cf0839e4a062c23ec48cbaca72bd641f28a30
Reviewed-on: https://chromium-review.googlesource.com/1165586Reviewed-by: Dave Tapuska <dtapuska@chromium.org>
Commit-Queue: Xida Chen <xidachen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#581676}

content/browser/renderer_host/input/touch_action_filter.cc

@@ -6,6 +6,7 @@
 
 #include <math.h>
 
+#include "base/debug/crash_logging.h"
 #include "base/debug/dump_without_crashing.h"
 #include "base/logging.h"
 #include "base/metrics/histogram_macros.h"
@@ -42,7 +43,7 @@ TouchActionFilter::TouchActionFilter()
       force_enable_zoom_(false) {}
 
 TouchActionFilter::~TouchActionFilter() {
-  function_call_sequence_.clear();
+  gesture_sequence_.clear();
 }
 
 FilterGestureEventResult TouchActionFilter::FilterGestureEvent(
@@ -56,6 +57,7 @@ FilterGestureEventResult TouchActionFilter::FilterGestureEvent(
     case WebInputEvent::kGestureScrollBegin: {
       DCHECK(!suppress_manipulation_events_);
       DCHECK(!touchscreen_scroll_in_progress_);
+      gesture_sequence_.append("GSB ");
       touchscreen_scroll_in_progress_ = true;
       // TODO(https://crbug.com/851644): Make sure the value is properly set.
       if (!scrolling_touch_action_.has_value())
@@ -101,7 +103,7 @@ FilterGestureEventResult TouchActionFilter::FilterGestureEvent(
       break;
 
     case WebInputEvent::kGestureScrollEnd:
-      function_call_sequence_.clear();
+      gesture_sequence_.clear();
       DCHECK(touchscreen_scroll_in_progress_);
       touchscreen_scroll_in_progress_ = false;
       ReportGestureEventFiltered(suppress_manipulation_events_);
@@ -154,17 +156,10 @@ FilterGestureEventResult TouchActionFilter::FilterGestureEvent(
       scrolling_touch_action_ = allowed_touch_action_;
       // TODO(https://crbug.com/851644): Make sure the value is properly set.
       if (!scrolling_touch_action_.has_value()) {
-        auto index_of_set =
-            std::find(std::begin(function_call_sequence_),
-                      std::end(function_call_sequence_), kOnSetTouchActionCall);
-        auto index_of_reset =
-            std::find(std::begin(function_call_sequence_),
-                      std::end(function_call_sequence_), kResetTouchActionCall);
-        if (index_of_set != std::end(function_call_sequence_) &&
-            index_of_reset != std::end(function_call_sequence_) &&
-            index_of_reset > index_of_set) {
-          base::debug::DumpWithoutCrashing();
-        }
+        static auto* crash_key = base::debug::AllocateCrashKeyString(
+            "touchaction-gestures", base::debug::CrashKeySize::Size256);
+        base::debug::SetCrashKeyString(crash_key, gesture_sequence_);
+        base::debug::DumpWithoutCrashing();
         SetTouchAction(cc::kTouchActionAuto);
       }
       DCHECK(!drop_current_tap_ending_event_);
@@ -194,7 +189,7 @@ bool TouchActionFilter::FilterManipulationEventAndResetState() {
 
 void TouchActionFilter::OnSetTouchAction(cc::TouchAction touch_action) {
   if (touch_action != cc::kTouchActionAuto)
-    function_call_sequence_.push_back(kOnSetTouchActionCall);
+    gesture_sequence_.append("Set ");
   // TODO(https://crbug.com/849819): add a DCHECK for
   // |has_touch_event_handler_|.
   // For multiple fingers, we take the intersection of the touch actions for
@@ -253,7 +248,7 @@ void TouchActionFilter::ResetTouchAction() {
   // their begin event(s) suppressed will be suppressed until the next
   // sequenceo.
   if (has_touch_event_handler_) {
-    function_call_sequence_.push_back(kResetTouchActionCall);
+    gesture_sequence_.append("Reset ");
     allowed_touch_action_.reset();
     white_listed_touch_action_.reset();
   } else {

content/browser/renderer_host/input/touch_action_filter.h

@@ -113,14 +113,7 @@ class CONTENT_EXPORT TouchActionFilter {
   // Whitelisted touch action received from the compositor.
   base::Optional<cc::TouchAction> white_listed_touch_action_;
 
-  // DEBUG ONLY! Record the sequence of function calls, cleared at GSE. When it
-  // is GSB and |scrolling_touch_action_| has no value, check this sequence.
-  enum FunctionCalls {
-    kOnSetTouchActionCall,
-    kResetTouchActionCall,
-  };
-
-  std::vector<FunctionCalls> function_call_sequence_;
+  std::string gesture_sequence_;
 
   DISALLOW_COPY_AND_ASSIGN(TouchActionFilter);
 };