[fuchsia] Add support for Google API Key provided via command line

Add support for Google API Key when provided through the config file
read by WebEngine.

      key present.

Test: Manually tested. Safe Sites functionality works without another
Bug: 1160130
Change-Id: I8b0fef7aa4892e130e0b6d423dc63e733e05aca6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2613649
Commit-Queue: Sharon Yang <yangsharon@chromium.org>
Reviewed-by: Wez <wez@chromium.org>
Reviewed-by: Mihai Sardarescu <msarda@chromium.org>
Reviewed-by: David Dorwin <ddorwin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#843741}

google_apis/google_api_keys.h

@@ -9,6 +9,8 @@
 // google_api_keys_unittest.cc.
 #include <string>
 
+#include "build/build_config.h"
+
 // These functions enable you to retrieve keys to use for Google APIs
 // such as Translate and Safe Browsing.
 //
@@ -83,9 +85,10 @@ std::string GetSharingAPIKey();
 // Retrieves the Speech On-Device API (SODA) API Key.
 std::string GetSodaAPIKey();
 
-#if defined(OS_IOS)
+#if defined(OS_IOS) || defined(OS_FUCHSIA)
 // Sets the API key. This should be called as early as possible before this
-// API key is even accessed.
+// API key is even accessed. It must be called before GetAPIKey.
+// TODO(https://crbug.com/1166007): Enforce this is called before GetAPIKey.
 void SetAPIKey(const std::string& api_key);
 #endif