Support exporting Mojo bindings for the component build.

third_party/WebKit/public/BUILD.gn

Index: third_party/WebKit/public/BUILD.gn
diff --git a/third_party/WebKit/public/BUILD.gn b/third_party/WebKit/public/BUILD.gn
index 089089e8612f6ebc5ea95cbd779dec65860c13ff..336b3d5b5f601852568e1da04796018ea23b2d3b 100644
--- a/third_party/WebKit/public/BUILD.gn
+++ b/third_party/WebKit/public/BUILD.gn
@@ -185,6 +185,19 @@ mojom("mojo_bindings") {
   ]
 
   use_new_wrapper_types = false
+
+  # The chromium variant must be linked with content and use the same export
+  # settings in component build because of the WebBluetoothDeviceId typemap
+  # inside content.
+  export_class_attribute = "CONTENT_EXPORT"
+  export_define = "CONTENT_IMPLEMENTATION=1"
+  export_header = "content/common/content_export.h"
+
+  # Similarly, the blink variant must be linked with the platform component
+  # since it uses types from it in its typemaps.
+  export_class_attribute_blink = "BLINK_PLATFORM_EXPORT"
+  export_define_blink = "BLINK_PLATFORM_IMPLEMENTATION=1"
+  export_header_blink = "third_party/WebKit/public/platform/WebCommon.h"
 }
 
 # GYP version: WebKit/public/blink.gyp:new_wrapper_types_mojo_bindings
@@ -192,6 +205,14 @@ mojom("new_wrapper_types_mojo_bindings") {
   sources = [
     "platform/modules/presentation/presentation.mojom",
   ]
+
+  # See comment above.
+  export_class_attribute = "CONTENT_EXPORT"
+  export_define = "CONTENT_IMPLEMENTATION=1"
+  export_header = "content/common/content_export.h"
+  export_class_attribute_blink = "BLINK_PLATFORM_EXPORT"
+  export_define_blink = "BLINK_PLATFORM_IMPLEMENTATION=1"
+  export_header_blink = "third_party/WebKit/public/platform/WebCommon.h"
 }
 
 # GYP version: WebKit/public/blink.gyp:android_mojo_bindings_java
@@ -202,6 +223,14 @@ mojom("android_mojo_bindings") {
   ]
 
   use_new_wrapper_types = false
+
+  # See comment above.
+  export_class_attribute = "CONTENT_EXPORT"
+  export_define = "CONTENT_IMPLEMENTATION=1"
+  export_header = "content/common/content_export.h"
+  export_class_attribute_blink = "BLINK_PLATFORM_EXPORT"
+  export_define_blink = "BLINK_PLATFORM_IMPLEMENTATION=1"
+  export_header_blink = "third_party/WebKit/public/platform/WebCommon.h"
 }
 
 group("generate_mojo_bindings") {