[google_apis] Add BUILDFLAG for whether to define SetAPIKey()

Replace iOS and Fuchsia conditions with a new
SUPPORT_EXTERNAL_GOOGLE_API_KEY BUILDFLAG so the logic is only defined
in one location and can be referenced outside //google_apis.

No build logic is changed.
`#if BUILDFLAG(IS_IOS) || BUILDFLAG(IS_FUCHSIA)` is replaced with
`#if BUILDFLAG(SUPPORT_EXTERNAL_GOOGLE_API_KEY)`, which is defined as
`is_ios || is_fuchsia`.

Bug: 1294915
Change-Id: I9a57727d7df86bd22f04c32946af4b49b1b69f29
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3756795
Auto-Submit: David Dorwin <ddorwin@chromium.org>
Reviewed-by: Sylvain Defresne <sdefresne@chromium.org>
Commit-Queue: David Dorwin <ddorwin@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1045946}

fuchsia_web/webengine/web_engine_main_delegate.cc

@@ -22,6 +22,7 @@
 #include "fuchsia_web/webengine/common/web_engine_content_client.h"
 #include "fuchsia_web/webengine/renderer/web_engine_content_renderer_client.h"
 #include "fuchsia_web/webengine/switches.h"
+#include "google_apis/buildflags.h"
 #include "google_apis/google_api_keys.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/base/ui_base_paths.h"
@@ -80,8 +81,12 @@ absl::optional<int> WebEngineMainDelegate::BasicStartupComplete() {
   }
 
   if (command_line->HasSwitch(switches::kGoogleApiKey)) {
+#if BUILDFLAG(SUPPORT_EXTERNAL_GOOGLE_API_KEY)
     google_apis::SetAPIKey(
         command_line->GetSwitchValueASCII(switches::kGoogleApiKey));
+#else
+    LOG(WARNING) << "Ignored " << switches::kGoogleApiKey;
+#endif
   }
 
   SetCorsExemptHeaders(base::SplitString(

google_apis/BUILD.gn

@@ -2,6 +2,7 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+import("//build/buildflag_header.gni")
 import("//build/config/chrome_build.gni")
 import("//build/config/features.gni")
 import("//extensions/buildflags/buildflags.gni")
@@ -59,6 +60,16 @@ if (use_official_google_api_keys == "") {
   use_official_google_api_keys = check_internal_result == 1
 }
 
+declare_args() {
+  # Whether the SetAPIKey() method is defined.
+  support_external_google_api_key = is_ios || is_fuchsia
+}
+
+buildflag_header("buildflags") {
+  header = "buildflags.h"
+  flags = [ "SUPPORT_EXTERNAL_GOOGLE_API_KEY=$support_external_google_api_key" ]
+}
+
 config("key_defines") {
   defines = []
 
@@ -132,6 +143,8 @@ template("google_apis_tmpl") {
 
     configs += [ ":key_defines" ]
 
+    public_deps = [ ":buildflags" ]
+
     deps = [
       ":oauth2_mint_token_consent_result_proto",
       "//base",

google_apis/google_api_keys.cc

@@ -18,6 +18,7 @@
 #include "base/logging.h"
 #include "base/strings/stringize_macros.h"
 #include "build/branding_buildflags.h"
+#include "google_apis/buildflags.h"
 #include "google_apis/gaia/gaia_config.h"
 #include "google_apis/gaia/gaia_switches.h"
 
@@ -205,7 +206,7 @@ class APIKeyCache {
   }
 
   std::string api_key() const { return api_key_; }
-#if BUILDFLAG(IS_IOS) || BUILDFLAG(IS_FUCHSIA)
+#if BUILDFLAG(SUPPORT_EXTERNAL_GOOGLE_API_KEY)
   void set_api_key(const std::string& api_key) { api_key_ = api_key; }
 #endif
   std::string api_key_non_stable() const { return api_key_non_stable_; }
@@ -369,7 +370,7 @@ std::string GetFresnelAPIKey() {
   return g_api_key_cache.Get().api_key_fresnel();
 }
 
-#if BUILDFLAG(IS_IOS) || BUILDFLAG(IS_FUCHSIA)
+#if BUILDFLAG(SUPPORT_EXTERNAL_GOOGLE_API_KEY)
 void SetAPIKey(const std::string& api_key) {
   g_api_key_cache.Get().set_api_key(api_key);
 }

google_apis/google_api_keys.h

@@ -10,6 +10,7 @@
 #include <string>
 
 #include "build/build_config.h"
+#include "google_apis/buildflags.h"
 
 // These functions enable you to retrieve keys to use for Google APIs
 // such as Translate and Safe Browsing.
@@ -89,7 +90,7 @@ std::string GetReadAloudAPIKey();
 // Retrieves the Fresnel API Key.
 std::string GetFresnelAPIKey();
 
-#if BUILDFLAG(IS_IOS) || BUILDFLAG(IS_FUCHSIA)
+#if BUILDFLAG(SUPPORT_EXTERNAL_GOOGLE_API_KEY)
 // Sets the API key. This should be called as early as possible before this
 // API key is even accessed. It must be called before GetAPIKey.
 // TODO(https://crbug.com/1166007): Enforce this is called before GetAPIKey.