Remove common.css resource from inspector overlay

common.css will be contained in the main resource after the following
frontend CL gets merged: crrev.com/c/2484719 so direct references
can be removed in the backend code.

Bug: 1139862
Change-Id: I756c8ba56368f27016453220610c98623a19f1b4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2484429
Commit-Queue: Alex Rudenko <alexrudenko@chromium.org>
Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Reviewed-by: Mathias Bynens <mathias@chromium.org>
Cr-Commit-Position: refs/heads/master@{#818809}

third_party/blink/renderer/core/inspector/inspector_overlay_agent.cc

@@ -1090,9 +1090,6 @@ void InspectorOverlayAgent::LoadOverlayPageResource() {
 
   scoped_refptr<SharedBuffer> data = SharedBuffer::Create();
 
-  data->Append("<style>", static_cast<size_t>(7));
-  data->Append(UncompressResourceAsBinary(IDR_INSPECT_COMMON_CSS));
-  data->Append("</style>", static_cast<size_t>(8));
   data->Append("<script>", static_cast<size_t>(8));
   data->Append(UncompressResourceAsBinary(IDR_INSPECT_TOOL_MAIN_JS));
   data->Append("</script>", static_cast<size_t>(9));