Fix a bunch of generated file build flakes in //extensions

extensions/browser/guest_view/web_view/BUILD.gn

Index: extensions/browser/guest_view/web_view/BUILD.gn
diff --git a/extensions/browser/guest_view/web_view/BUILD.gn b/extensions/browser/guest_view/web_view/BUILD.gn
index 6ae8d76185e2ef70c68dbd2d98e89f6d1091fd30..15e229bc10d28312b2da7d6beb6abe24322af595 100644
--- a/extensions/browser/guest_view/web_view/BUILD.gn
+++ b/extensions/browser/guest_view/web_view/BUILD.gn
@@ -25,7 +25,10 @@ source_set("web_view") {
   ]
 
   deps = [
+    "//components/guest_view/browser",

[Devlin, 2016/10/26 19:30:28]

Do none of the other extensions/browser/guest_view files need this?  (More
surprised than anything else)

[tsniatowski, 2016/10/26 20:43:41]

Apparently not from an "are there missing dependencies that can break the build"
perspective according to my test; from a gn check perspective -- maybe, I'm not
handling it.

Actually after a recheck this particular dep is not needed to fix the flakiness.
Keep it?

[Devlin, 2016/10/26 21:57:52]

Let's hoist this up to extensions/browser/guest_view/BUILD.gn - we *do* depend
on it.

+    "//components/web_cache/browser",
     "//content/public/common",
     "//extensions/common/api",
+    "//extensions/strings",
   ]
 }