[DevTools] chaotic green dots displacement fix

third_party/WebKit/Source/devtools/front_end/sources/JavaScriptSourceFrame.js

Index: third_party/WebKit/Source/devtools/front_end/sources/JavaScriptSourceFrame.js
diff --git a/third_party/WebKit/Source/devtools/front_end/sources/JavaScriptSourceFrame.js b/third_party/WebKit/Source/devtools/front_end/sources/JavaScriptSourceFrame.js
index 265139b8b5ed9b1381d9e6a67942c229eb092e6c..1b2199ec287174d8642ec1475cd0ea6079aef9f7 100644
--- a/third_party/WebKit/Source/devtools/front_end/sources/JavaScriptSourceFrame.js
+++ b/third_party/WebKit/Source/devtools/front_end/sources/JavaScriptSourceFrame.js
@@ -595,6 +595,10 @@ Sources.JavaScriptSourceFrame = class extends SourceFrame.UISourceCodeFrame {
     var callFrame = UI.context.flavor(SDK.DebuggerModel.CallFrame);
     if (!callFrame)
       return;
+    if (this._clearContinueToLocationsTimer) {
+      clearTimeout(this._clearContinueToLocationsTimer);
+      delete this._clearContinueToLocationsTimer;
+    }

[lushnikov, 2017/03/10 04:51:57]

Why don't we want greendots to be removed in case of absence of localScope?

Also, how is this fixing the race? Green dots will or will not be removed
depending on the timegap between _showContinueToLocations invocation.

[kozy, 2017/03/10 05:06:38]

Let me explain. When we clearExecutionLine we schedule green dots removing in 1
sec, if new execution line arrive before 1 second - we clear this timeout in
this function and show correct green dots, otherwise we cleanup green dots.
Issue was in the fact that we don't cancel green dots removing in case when
localScope is empty - e.g. scope when top level frame just inside of the script
and script doesn't have local variables by itself - but we should, otherwise
next time when we call show green dots - we override clear timeout with new one
and just never clear original one.

     var localScope = callFrame.localScope();
     if (!localScope)
       return;
@@ -605,11 +609,6 @@ Sources.JavaScriptSourceFrame = class extends SourceFrame.UISourceCodeFrame {
     debuggerModel.getPossibleBreakpoints(start, end, true)
         .then(locations => this.textEditor.operation(renderLocations.bind(this, locations)));
 
-    if (this._clearContinueToLocationsTimer) {
-      clearTimeout(this._clearContinueToLocationsTimer);
-      delete this._clearContinueToLocationsTimer;
-    }
-
     /**
      * @param {!Array<!SDK.DebuggerModel.BreakLocation>} locations
      * @this {Sources.JavaScriptSourceFrame}