DevTools: fix 'Failed to write into a temp file' when recording a filmstrip

BUG=524107

Review URL: https://codereview.chromium.org/1310343007

git-svn-id: svn://svn.chromium.org/blink/trunk@201758 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/Source/devtools/front_end/bindings/TempFile.js

@@ -382,6 +382,7 @@ WebInspector.DeferredTempFile.prototype = {
         }
         if (this._tempFile)
             this._tempFile.remove();
+        this._tempFile = null;
     }
 }
 

third_party/WebKit/Source/devtools/front_end/network/NetworkPanel.js

@@ -730,6 +730,9 @@ WebInspector.NetworkPanel.FilmStripRecorder.prototype = {
             return;
 
         this._target = WebInspector.targetManager.mainTarget();
+        if (this._tracingModel)
+            this._tracingModel.reset();
+        else
             this._tracingModel = new WebInspector.TracingModel(new WebInspector.TempFileBackingStorage("tracing"));
         this._target.tracingManager.start(this, "-*,disabled-by-default-devtools.screenshot", "");
         this._filmStripView.reset();

third_party/WebKit/Source/devtools/front_end/sdk/TracingModel.js

@@ -10,8 +10,10 @@
  */
 WebInspector.TracingModel = function(backingStorage)
 {
-    this._backingStorage = backingStorage;
     this.reset();
+    // Set backing storage after reset so that we do not perform
+    // an extra reset of backing storage -- this is not free.
+    this._backingStorage = backingStorage;
 }
 
 /**
@@ -190,6 +192,7 @@ WebInspector.TracingModel.prototype = {
         this._minimumRecordTime = 0;
         this._maximumRecordTime = 0;
         this._devToolsMetadataEvents = [];
+        if (this._backingStorage)
             this._backingStorage.reset();
         this._appendDelimiter = false;
         /** @type {!Array<!WebInspector.TracingModel.Event>} */