Reland "Update roll & type check scripts with new browser_protocol.pdl location"

This reverts commit db38f98828b6da095ed671ead754749b29c46f91.

Reason for revert: re-landing as upstream change appears to stick this time.

Original change's description:
> Revert "Update roll & type check scripts with new browser_protocol.pdl location"
> 
> This reverts commit a4d8446198d2a774c00e27effd696f56932afcbe.
> 
> Reason for revert: Upstream change that this depends on got reverted: https://chromium-review.googlesource.com/c/chromium/src/+/1935479
> 
> Original change's description:
> > Update roll & type check scripts with new browser_protocol.pdl location
> > 
> > This is a follow-up to https://chromium-review.googlesource.com/c/chromium/src/+/1898538
> > to update the location of the browser_protocol.pdl.
> > 
> > NOPRESUBMIT=true
> > Bug: https://crbug.com/1018108
> > Change-Id: Id21b5bc65d6af472b55151a458beca34dabc6d1d
> > Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/1904098
> > Commit-Queue: Andrey Kosyakov <caseq@chromium.org>
> > Reviewed-by: Yang Guo <yangguo@chromium.org>
> 
> TBR=caseq@chromium.org,yangguo@chromium.org
> 
> Change-Id: I276ca14aa57ed6dcfd76946c8bee9ea580643b6b
> No-Presubmit: true
> No-Tree-Checks: true
> No-Try: true
> Bug: https://crbug.com/1018108
> Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/1936211
> Reviewed-by: Yang Guo <yangguo@chromium.org>
> Commit-Queue: Yang Guo <yangguo@chromium.org>

TBR=caseq@chromium.org,yangguo@chromium.org

Change-Id: Icb1d908317514f15a80fb8edc84974045309487e
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: https://crbug.com/1018108
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/1938351
Commit-Queue: Andrey Kosyakov <caseq@chromium.org>
Reviewed-by: Andrey Kosyakov <caseq@chromium.org>
diff --git a/scripts/devtools_paths.py b/scripts/devtools_paths.py
index b62c397..e4f4754 100644
--- a/scripts/devtools_paths.py
+++ b/scripts/devtools_paths.py
@@ -81,3 +81,6 @@
 
 def package_json_path():
     return path.join(devtools_root_path(), 'package.json')
+
+def browser_protocol_path():
+    return path.join(third_party_path(), 'blink', 'public', 'devtools_protocol', 'browser_protocol.pdl')