apple: Convert GN libs lists to frameworks in //base.

GN recently added support for Apple frameworks to link, rather than
overloading the libs lists. This pulls .frameworks out of the libs
lists, so that GN can stop supporting .frameworks in libs in the
future.

Bug: 1052560
Change-Id: Icb922242c8dbcfc9c4be81b355ca83c1aedd1c1d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2276315
Commit-Queue: Nico Weber <thakis@chromium.org>
Reviewed-by: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#784205}

base/BUILD.gn

@@ -2385,7 +2385,7 @@ component("i18n") {
   configs += [ "//build/config/compiler:no_size_t_to_int_warning" ]
 
   if (is_mac) {
-    libs = [ "CoreFoundation.framework" ]
+    frameworks = [ "CoreFoundation.framework" ]
   }
 }
 
@@ -3166,7 +3166,7 @@ test("base_unittests") {
 
   if (is_mac) {
     sources += [ "message_loop/message_pump_kqueue_unittest.cc" ]
-    libs = [
+    frameworks = [
       "CoreFoundation.framework",
       "Foundation.framework",
     ]

base/test/BUILD.gn

@@ -192,7 +192,7 @@ static_library("test_support") {
   }
 
   if (is_mac) {
-    libs = [ "AppKit.framework" ]
+    frameworks = [ "AppKit.framework" ]
     sources += [
       "mock_chrome_application_mac.h",
       "mock_chrome_application_mac.mm",
@@ -525,7 +525,7 @@ if (is_ios) {
       ":google_test_runner_shared_headers",
       "//base",
     ]
-    libs = [ "UIKit.framework" ]
+    frameworks = [ "UIKit.framework" ]
     configs += [
       "//build/config/compiler:enable_arc",
       "//build/config/ios:xctest_config",