[DevTools] Listen to mousedown in SoftContextMenu once

We used to handle that through GlassPane, which has problems
with multiple layers of SoftContextMenus. Now we have a single
listener on bubble, and cancel all menus at that point.

BUG=709350

Review-Url: https://codereview.chromium.org/2801373002
Cr-Commit-Position: refs/heads/master@{#463032}

third_party/WebKit/Source/devtools/front_end/ui/GlassPane.js

@@ -123,7 +123,7 @@ UI.GlassPane = class {
       return;
     // Deliberately starts with 3000 to hide other z-indexed elements below.
     this.element.style.zIndex = 3000 + 1000 * UI.GlassPane._panes.size;
-    document.body.addEventListener('click', this._onMouseDownBound, true);
+    document.body.addEventListener('mousedown', this._onMouseDownBound, true);
     this._widget.show(document.body);
     UI.GlassPane._panes.add(this);
     this._positionContent();
@@ -133,7 +133,7 @@ UI.GlassPane = class {
     if (!this.isShowing())
       return;
     UI.GlassPane._panes.delete(this);
-    this.element.ownerDocument.body.removeEventListener('click', this._onMouseDownBound, true);
+    this.element.ownerDocument.body.removeEventListener('mousedown', this._onMouseDownBound, true);
     this._widget.detach();
   }
 

third_party/WebKit/Source/devtools/front_end/ui/SoftContextMenu.js

@@ -50,10 +50,6 @@ UI.SoftContextMenu = class {
 
     this._glassPane = new UI.GlassPane();
     this._glassPane.setBlockPointerEvents(!this._parentMenu);
-    this._glassPane.setSetOutsideClickCallback(event => {
-      this._discardMenu(true, event);
-      event.consume();
-    });
     this._glassPane.registerRequiredCSS('ui/softContextMenu.css');
     this._glassPane.setContentAnchorBox(anchorBox);
     this._glassPane.setSizeBehavior(UI.GlassPane.SizeBehavior.MeasureContent);
@@ -71,6 +67,11 @@ UI.SoftContextMenu = class {
 
     this._glassPane.show(document);
     this._focus();
+
+    if (!this._parentMenu) {
+      this._onBodyMouseDown = event => this._discardMenu(true, event);
+      this._document.body.addEventListener('mousedown', this._onBodyMouseDown, false);
+    }
   }
 
   discard() {
@@ -330,6 +331,10 @@ UI.SoftContextMenu = class {
     if (this._glassPane) {
       this._glassPane.hide();
       delete this._glassPane;
+      if (this._onBodyMouseDown) {
+        this._document.body.removeEventListener('mousedown', this._onBodyMouseDown, false);
+        delete this._onBodyMouseDown;
+      }
     }
     if (this._parentMenu)
       delete this._parentMenu._subMenu;