DevTools: introduce CSSStyleSheetHeader.originalContentProvider() method

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

Index: third_party/WebKit/Source/devtools/front_end/sdk/CSSModel.js
diff --git a/third_party/WebKit/Source/devtools/front_end/sdk/CSSModel.js b/third_party/WebKit/Source/devtools/front_end/sdk/CSSModel.js
index a919dfa91f1dc99e74f358fedfd9cbfcb02e433e..fe993b267d1e3697daffaa49a05240f3ead32494 100644
--- a/third_party/WebKit/Source/devtools/front_end/sdk/CSSModel.js
+++ b/third_party/WebKit/Source/devtools/front_end/sdk/CSSModel.js
@@ -47,6 +47,9 @@ WebInspector.CSSModel = function(target)
     /** @type {!Map.<string, !Object.<!PageAgent.FrameId, !Array.<!CSSAgent.StyleSheetId>>>} */
     this._styleSheetIdsForURL = new Map();
 
+    /** @type {!Map.<!WebInspector.CSSStyleSheetHeader, !Promise<string>>} */
+    this._originalStyleSheetText = new Map();
+
     /** @type {!Multimap<string, !CSSAgent.StyleSheetId>} */
     this._sourceMapLoadingStyleSheetsIds = new Multimap();
 
@@ -385,15 +388,18 @@ WebInspector.CSSModel.prototype = {
 
         console.assert(styleSheetIds.length === ranges.length && ranges.length === texts.length, "Array lengths must be equal");
         var edits = [];
+        var ensureContentPromises = [];
         for (var i = 0; i < styleSheetIds.length; ++i) {
             edits.push({
                 styleSheetId: styleSheetIds[i],
                 range: ranges[i].serializeToObject(),
                 text: texts[i]
             });
+            ensureContentPromises.push(this._ensureOriginalStyleSheetText(styleSheetIds[i]));
         }
 
-        return this._agent.setStyleTexts(edits, parsePayload.bind(this))
+        return Promise.all(ensureContentPromises)
+            .then(() => this._agent.setStyleTexts(edits, parsePayload.bind(this)))
             .catchException(false);
     },
 
@@ -422,7 +428,8 @@ WebInspector.CSSModel.prototype = {
         }
 
         WebInspector.userMetrics.actionTaken(WebInspector.UserMetrics.Action.StyleRuleEdited);
-        return this._agent.setRuleSelector(styleSheetId, range, text, callback.bind(this))
+        return this._ensureOriginalStyleSheetText(styleSheetId)
+            .then(() => this._agent.setRuleSelector(styleSheetId, range, text, callback.bind(this)))
             .catchException(false);
     },
 
@@ -451,7 +458,8 @@ WebInspector.CSSModel.prototype = {
         }
 
         WebInspector.userMetrics.actionTaken(WebInspector.UserMetrics.Action.StyleRuleEdited);
-        return this._agent.setKeyframeKey(styleSheetId, range, text, callback.bind(this))
+        return this._ensureOriginalStyleSheetText(styleSheetId)
+            .then(() => this._agent.setKeyframeKey(styleSheetId, range, text, callback.bind(this)))
             .catchException(false);
     },
 
@@ -684,7 +692,8 @@ WebInspector.CSSModel.prototype = {
         }
 
         WebInspector.userMetrics.actionTaken(WebInspector.UserMetrics.Action.StyleRuleEdited);
-        return this._agent.setMediaText(styleSheetId, range, newMediaText, parsePayload.bind(this))
+        return this._ensureOriginalStyleSheetText(styleSheetId)
+            .then(() => this._agent.setMediaText(styleSheetId, range, newMediaText, parsePayload.bind(this)))
             .catchException(false);
     },
 
@@ -696,7 +705,8 @@ WebInspector.CSSModel.prototype = {
      */
     addRule: function(styleSheetId, ruleText, ruleLocation)
     {
-        return this._agent.addRule(styleSheetId, ruleText, ruleLocation, parsePayload.bind(this))
+        return this._ensureOriginalStyleSheetText(styleSheetId)
+            .then(() => this._agent.addRule(styleSheetId, ruleText, ruleLocation, parsePayload.bind(this)))
             .catchException(/** @type {?WebInspector.CSSStyleRule} */(null))
 
         /**
@@ -792,6 +802,32 @@ WebInspector.CSSModel.prototype = {
     },
 
     /**
+     * @param {!CSSAgent.StyleSheetId} styleSheetId
+     * @return {!Promise<string>}
+     */
+    _ensureOriginalStyleSheetText: function(styleSheetId)
+    {
+        var header = this.styleSheetHeaderForId(styleSheetId);
+        if (!header)
+            return Promise.resolve("");
+        var promise = this._originalStyleSheetText.get(header);
+        if (!promise) {
+            promise = this.getStyleSheetText(header.id);
+            this._originalStyleSheetText.set(header, promise);
+        }
+        return promise;
+    },
+
+    /**
+     * @param {!WebInspector.CSSStyleSheetHeader} header
+     * @return {!Promise<string>}
+     */
+    originalStyleSheetText: function(header)
+    {
+        return this._ensureOriginalStyleSheetText(header.id);
+    },
+
+    /**
      * @param {!CSSAgent.CSSStyleSheetHeader} header
      */
     _styleSheetAdded: function(header)
@@ -832,6 +868,7 @@ WebInspector.CSSModel.prototype = {
             if (!Object.keys(frameIdToStyleSheetIds).length)
                 this._styleSheetIdsForURL.remove(url);
         }
+        this._originalStyleSheetText.remove(header);
         this._detachSourceMap(header);
         this.dispatchEventToListeners(WebInspector.CSSModel.Events.StyleSheetRemoved, header);
     },
@@ -865,7 +902,8 @@ WebInspector.CSSModel.prototype = {
         newText = WebInspector.CSSModel.trimSourceURL(newText);
         if (header.hasSourceURL)
             newText += "\n/*# sourceURL=" + header.sourceURL + " */";
-        return this._agent.setStyleSheetText(header.id, newText, callback.bind(this));
+        return this._ensureOriginalStyleSheetText(styleSheetId)
+            .then(() => this._agent.setStyleSheetText(header.id, newText, callback.bind(this)));
 
         /**
          * @param {?Protocol.Error} error