mac: Convert GN libs lists to frameworks in //gpu.

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: I172aa483c71f880b78668f857b8378ee1b9fe562
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2276659
Commit-Queue: Kenneth Russell <kbr@chromium.org>
Auto-Submit: Robert Sesek <rsesek@chromium.org>
Reviewed-by: Kenneth Russell <kbr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#784493}

gpu/BUILD.gn

@@ -267,7 +267,7 @@ if (!is_android && !is_fuchsia && !is_chromeos) {
     defines = [ "GL_GLEXT_PROTOTYPES" ]
 
     if (is_mac) {
-      libs = [ "IOSurface.framework" ]
+      frameworks = [ "IOSurface.framework" ]
     }
 
     deps = [

gpu/command_buffer/service/BUILD.gn

@@ -385,7 +385,7 @@ target(link_target_type, "gles2_sources") {
     ]
 
     # Required by gles2_cmd_decoder.cc on Mac.
-    libs = [
+    frameworks = [
       "Cocoa.framework",
       "IOSurface.framework",
       "Metal.framework",

gpu/config/BUILD.gn

@@ -214,7 +214,7 @@ jumbo_source_set("config_sources") {
     }
   }
   if (is_mac) {
-    libs = [ "OpenGL.framework" ]
+    frameworks = [ "OpenGL.framework" ]
   }
   if (is_linux || is_mac) {
     deps += [ "//third_party/angle:angle_gpu_info_util" ]

gpu/ipc/common/BUILD.gn

@@ -85,7 +85,7 @@ source_set("ipc_common_sources") {
       "gpu_memory_buffer_impl_io_surface.cc",
       "gpu_memory_buffer_impl_io_surface.h",
     ]
-    libs = [ "IOSurface.framework" ]
+    frameworks = [ "IOSurface.framework" ]
   }
   if (is_win) {
     sources += [