add google analytics polyfill, fixes brave/brave-browser#4402 (uplift to 0.67.x)

[brave-builds]

Uplift of #2488

Approved, please ensure that before merging:

• You have checked CI and the builds, lint, and tests all pass or are not related to your PR.
• You have tested your change on Nightly.
• The PR milestones match the branch they are landing to.

After you merge:

• The associated issue milestone is set to the smallest version that the changes is landed on.

[kjozwiak]

Uplifting into 0.67.x approved. Also went through #2488 (comment) via 0.68.64 Chromium: 75.0.3770.100. Please make sure that all the correct labels are being used and the appropriate issue is moved into the correct milestone.

@snyderp before merging, can you take a look at the Jenkins failure? Seems like it failed on:

03:33:08  FAILED: obj/brave/renderer/renderer/brave_content_renderer_client.o 

03:33:08 FAILED: obj/brave/renderer/renderer/brave_content_renderer_client.o

[bsclifton]

Looks like the actual error is:

00:33:08  In file included from ../../brave/renderer/brave_content_settings_observer.cc:6:
00:33:08  In file included from ../../brave/renderer/brave_content_settings_observer.h:9:
00:33:08  ../../chrome/renderer/content_settings_observer.h:16:10: fatal error: 'chrome/common/content_settings_renderer.mojom.h' file not found
00:33:08  #include "chrome/common/content_settings_renderer.mojom.h"
00:33:08           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
00:33:08  1 error generated.

Restarted the job...

[bsclifton]

macOS had some issues - going to check this out locally and run the steps manually...

[bsclifton]

Ran all tests locally - everything looks great! 👍