Expose way to set google api key through CWVWebView class method.

ios/web_view/internal/cwv_web_view.mm

Index: ios/web_view/internal/cwv_web_view.mm
diff --git a/ios/web_view/internal/cwv_web_view.mm b/ios/web_view/internal/cwv_web_view.mm
index 08fb4d8dc30b2994005f51fbd5799b2b1efbc42c..106276d11d3180151a4ce03fa7935af503623a01 100644
--- a/ios/web_view/internal/cwv_web_view.mm
+++ b/ios/web_view/internal/cwv_web_view.mm
@@ -7,9 +7,11 @@
 #include <memory>
 #include <utility>
 
+#include "base/environment.h"
 #import "base/ios/weak_nsobject.h"
 #include "base/memory/ptr_util.h"
 #include "base/strings/sys_string_conversions.h"
+#include "google_apis/google_api_keys.h"
 #import "ios/web/public/navigation_manager.h"
 #include "ios/web/public/referrer.h"
 #include "ios/web/public/reload_type.h"
@@ -60,6 +62,28 @@
 @synthesize estimatedProgress = _estimatedProgress;
 @synthesize UIDelegate = _UIDelegate;
 
++ (void)setGoogleAPIKey:(NSString*)googleAPIKey
+               clientID:(NSString*)clientID
+           clientSecret:(NSString*)clientSecret {
+  std::unique_ptr<base::Environment> environment(base::Environment::Create());
+
+  environment->SetVar("GOOGLE_API_KEY", base::SysNSStringToUTF8(googleAPIKey));
+  environment->SetVar("GOOGLE_DEFAULT_CLIENT_ID",
+                      base::SysNSStringToUTF8(clientID));
+  environment->SetVar("GOOGLE_DEFAULT_CLIENT_SECRET",
+                      base::SysNSStringToUTF8(clientSecret));
+
+  DCHECK_EQ(google_apis::GetAPIKey(), base::SysNSStringToUTF8(googleAPIKey));
+  DCHECK_EQ(google_apis::GetOAuth2ClientID(google_apis::CLIENT_MAIN),
+            base::SysNSStringToUTF8(clientID));
+  DCHECK_EQ(google_apis::GetOAuth2ClientSecret(google_apis::CLIENT_MAIN),
+            base::SysNSStringToUTF8(clientSecret));
+
+  environment->UnSetVar("GOOGLE_API_KEY");

[Hiroshi Ichikawa, 2017/03/31 08:15:26]

I'm a bit confused how this code takes effect, by setting environment variables
and unsetting immediately. Maybe calling google_apis::GetAPIKey() etc. is a
trick, to let it read environment variables and cache them?

It should be commented as such, or maybe how about just setting these
environment variables here and leave them, without unsetting them? Why do you
need to unset them?

[michaeldo, 2017/03/31 20:28:16]

You are on the right track. By calling GetAPIKey, it is fetched and cached. See
https://cs.chromium.org/chromium/src/google_apis/google_api_keys.cc?l=292 and
APIKeyCache constructor on line 100.

I actually think the DCHECK is good here to ensure that the API is working as
expected. Maybe leaving them set exposes them to the whole environment longer
than necessary, but I agree with Eugene, maybe Sylvain can speak to the reasons
to unset them.

[Hiroshi Ichikawa, 2017/04/03 05:28:16]

Can you move google_apis::GetAPIKey() etc. out of DCHECK_EQ()? If I understand
correctly, expressions inside DCHECK_EQ() are not executed in release build. So
the current code only works on debug build, not release build.

On 2017/03/31 20:28:16, michaeldo wrote:
I see, thanks. It should be definitely commented as such. It's tricky to rely on
such side effect of getter functions.
I feel this kind of DCHECK is more like a role of unit tests. So I slightly
prefer to extract these DCHECKs into a unit test, but it's up to you.

[jzw1, 2017/04/11 08:28:46]

Yeah I'm OK with removing the DCHECKs and the UnSetVars.

+  environment->UnSetVar("GOOGLE_DEFAULT_CLIENT_ID");
+  environment->UnSetVar("GOOGLE_DEFAULT_CLIENT_SECRET");
+}
+
 - (instancetype)initWithFrame:(CGRect)frame
                 configuration:(CWVWebViewConfiguration*)configuration {
   self = [super initWithFrame:frame];