[DevTools] Fix null tooltip errors

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

Index: third_party/WebKit/Source/devtools/front_end/ui/Tooltip.js
diff --git a/third_party/WebKit/Source/devtools/front_end/ui/Tooltip.js b/third_party/WebKit/Source/devtools/front_end/ui/Tooltip.js
index 4e41b8265d35cbd639ebad6cfb948363360ba6da..0ea1c53d711b5ae585a98d5755e764a3e5d1a5ca 100644
--- a/third_party/WebKit/Source/devtools/front_end/ui/Tooltip.js
+++ b/third_party/WebKit/Source/devtools/front_end/ui/Tooltip.js
@@ -29,13 +29,16 @@ UI.Tooltip = class {
   }
 
   /**
+   * Installs the tooltipContent to be shown on mouseover, called when title is set on an Element.

[lushnikov, 2016/12/06 01:19:37]

style: please, drop the documentation comment (i know, that sounds shocking, but
we don't use any)

[paulirish, 2016/12/06 01:37:27]

Isn't that old policy? Blink is open to comments for documentation now, aren't
we?

[lushnikov, 2016/12/06 22:30:23]

Let's discuss this on Thursday!

We should either write comments consistently or disregard them altogether.
I'd rather not, since front-end is not *that* big and moves quite fast.

[phulce, 2016/12/06 23:09:32]

Done.

+   * Removes the tooltip if content is null or empty.
+   *
    * @param {!Element} element
-   * @param {!Element|string} tooltipContent
+   * @param {?Element|string} tooltipContent
    * @param {string=} actionId
    * @param {!Object=} options
    */
   static install(element, tooltipContent, actionId, options) {
-    if (typeof tooltipContent === 'string' && tooltipContent === '') {
+    if (tooltipContent === null || tooltipContent === '') {

[lushnikov, 2016/12/06 01:19:36]

if (!tooltipContent) {
   ...
}

[phulce, 2016/12/06 23:09:32]

Done.

       delete element[UI.Tooltip._symbol];
       return;
     }