DevTools: Add feature to capture full-height screenshots

third_party/WebKit/Source/devtools/front_end/emulation/DeviceModeView.js

Index: third_party/WebKit/Source/devtools/front_end/emulation/DeviceModeView.js
diff --git a/third_party/WebKit/Source/devtools/front_end/emulation/DeviceModeView.js b/third_party/WebKit/Source/devtools/front_end/emulation/DeviceModeView.js
index e554590f7ba4a7bd9af511f32418a3ecd1fc4bf2..bd1495dad53a66520cea358bb97f843c15f85e88 100644
--- a/third_party/WebKit/Source/devtools/front_end/emulation/DeviceModeView.js
+++ b/third_party/WebKit/Source/devtools/front_end/emulation/DeviceModeView.js
@@ -470,6 +470,47 @@ Emulation.DeviceModeView = class extends UI.VBox {
       }
     }
   }
+
+  captureFullHeightScreenshot() {
+    var mainTarget = SDK.targetManager.mainTarget();
+    if (!mainTarget)
+      return;
+    SDK.DOMModel.muteHighlight();
+    this._model.captureFullHeightScreenshot(screenshotCaptured.bind(this));
+
+    /**
+     * @param {?Protocol.Error} error
+     * @param {string} content
+     * @this {Emulation.DeviceModeView}
+     */
+    function screenshotCaptured(error, content) {
+      SDK.DOMModel.unmuteHighlight();
+      if (error) {
+        console.error(error);
+        return;
+      }
+      var canvas = createElement('canvas');
+      var pageImage = new Image();
+      pageImage.src = 'data:image/png;base64,' + content;
+      pageImage.onload = () => {
+        var ctx = canvas.getContext('2d');
+        ctx.imageSmoothingEnabled = false;
+        canvas.width = pageImage.width;
+        canvas.height = pageImage.height;
+        ctx.drawImage(pageImage, 0, 0);
+        var url = mainTarget && mainTarget.inspectedURL();
+        var fileName = url ? url.trimURL().removeURLFragment() : '';
+        if (this._model.type() === Emulation.DeviceModeModel.Type.Device)
+          fileName += Common.UIString('(%s)', this._model.device().title);
+        var link = createElement('a');
+        link.download = fileName + '.png';
+        canvas.toBlob(function(blob) {
+          link.href = URL.createObjectURL(blob);
+          link.click();
+        });
+      }
+    }
+  }
 };
 
 /**