Provide a method to remove inserted style sheet

third_party/WebKit/public/web/WebDocument.h

Index: third_party/WebKit/public/web/WebDocument.h
diff --git a/third_party/WebKit/public/web/WebDocument.h b/third_party/WebKit/public/web/WebDocument.h
index af9497b88337b948de03fb3dc6a995a22bfce308..717cb948b06467eaa2f68e46408a9033b1235e9f 100644
--- a/third_party/WebKit/public/web/WebDocument.h
+++ b/third_party/WebKit/public/web/WebDocument.h
@@ -120,8 +120,14 @@ class WebDocument : public WebNode {
   // Gets the accessibility object that has focus.
   BLINK_EXPORT WebAXObject FocusedAccessibilityObject() const;
 
-  // Inserts the given CSS source code as a stylesheet in the document.
-  BLINK_EXPORT void InsertStyleSheet(const WebString& source_code);
+  // Inserts the given CSS source code as a stylesheet in the document, and
+  // return its id.
+  BLINK_EXPORT int InsertStyleSheet(const WebString& source_code);

[rune, 2017/05/16 09:00:59]

Could you use a typedef with a suitable id type name instead?

[limasdf, 2017/05/18 12:32:53]

Done.

+
+  // Removes the CSS which was previously inserted by a call to
+  // InsertStyleSheet(). Returns true on success. False means that there's no
+  // corresponding stylesheet.
+  BLINK_EXPORT bool RemoveInsertedStyleSheet(int id);

[rune, 2017/05/16 09:00:59]

Is a return value necessary here?

[limasdf, 2017/05/18 12:32:53]

I was thinking the extension api should return an error message when the user
inserts wrong id.
But it could be done by holding id from extension side. 
So, bool -> void (done).

[rune, 2017/05/16 09:00:59]

These API methods should have a unit test.

[limasdf, 2017/05/18 12:32:53]

Done.

   // Arranges to call WebFrameClient::didMatchCSS(frame(), ...) when one of
   // the selectors matches or stops matching an element in this document.