Make //device/core a component.

//device/core/device_client.cc defines a global variable. Thus, in
component builds there should be only on instance of this compilation
unit but if it is built as a static library there is the possibility
that different parts of Chrome use different instances.

BUG=538339

Review URL: https://codereview.chromium.org/1390423003

Cr-Commit-Position: refs/heads/master@{#354338}

5 files changed, 44 insertions, 11 deletions

diff --git a/device/core/BUILD.gn b/device/core/BUILD.gn
index d931807..e85acb6 100644
--- a/device/core/BUILD.gn
+++ b/device/core/BUILD.gn
@@ -2,7 +2,9 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-source_set("core") {
+component("core") {
+  output_name = "device_core"
+
   sources = [
     "device_client.cc",
     "device_client.h",
@@ -10,6 +12,8 @@ source_set("core") {
     "device_monitor_win.h",
   ]
 
+  defines = [ "DEVICE_CORE_IMPLEMENTATION" ]
+
   public_deps = [
     "//base",
   ]
diff --git a/device/core/core.gyp b/device/core/core.gyp
index 034b9e3..d27073d 100644
--- a/device/core/core.gyp
+++ b/device/core/core.gyp
@@ -9,10 +9,13 @@
   'targets': [
     {
       'target_name': 'device_core',
-      'type': 'static_library',
+      'type': '<(component)',
       'include_dirs': [
         '../..',
       ],
+      'defines': [
+        'DEVICE_CORE_IMPLEMENTATION',
+      ],
       'sources': [
         'device_client.cc',
         'device_client.h',
@@ -20,8 +23,8 @@
         'device_monitor_win.h',
       ],
       'dependencies': [
-        '<(DEPTH)/third_party/mojo/mojo_public.gyp:mojo_cpp_bindings',
-      ],
+        '../../base/base.gyp:base',
+      ]
     },
   ],
 }
diff --git a/device/core/device_client.h b/device/core/device_client.h
index d63471b..9fdc7f1 100644
--- a/device/core/device_client.h
+++ b/device/core/device_client.h
@@ -6,20 +6,17 @@
 #define DEVICE_CORE_DEVICE_CLIENT_H_
 
 #include "base/macros.h"
+#include "device/core/device_core_export.h"
 
 namespace device {
 
 class HidService;
 class UsbService;
 
-namespace usb {
-class DeviceManager;
-}
-
 // Interface used by consumers of //device APIs to get pointers to the service
 // singletons appropriate for a given embedding application. For an example see
 // //chrome/browser/chrome_device_client.h.
-class DeviceClient {
+class DEVICE_CORE_EXPORT DeviceClient {
  public:
   // Construction sets the single instance.
   DeviceClient();
diff --git a/device/core/device_core_export.h b/device/core/device_core_export.h
new file mode 100644
index 0000000..6f1cddb
--- /dev/null
+++ b/device/core/device_core_export.h
@@ -0,0 +1,28 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef DEVICE_CORE_DEVICE_CORE_EXPORT_H_
+#define DEVICE_CORE_DEVICE_CORE_EXPORT_H_
+
+#if defined(COMPONENT_BUILD) && defined(WIN32)
+
+#if defined(DEVICE_CORE_IMPLEMENTATION)
+#define DEVICE_CORE_EXPORT __declspec(dllexport)
+#else
+#define DEVICE_CORE_EXPORT __declspec(dllimport)
+#endif
+
+#elif defined(COMPONENT_BUILD) && !defined(WIN32)
+
+#if defined(DEVICE_CORE_IMPLEMENTATION)
+#define DEVICE_CORE_EXPORT __attribute__((visibility("default")))
+#else
+#define DEVICE_CORE_EXPORT
+#endif
+
+#else
+#define DEVICE_CORE_EXPORT
+#endif
+
+#endif  // DEVICE_CORE_DEVICE_CORE_EXPORT_H_
diff --git a/device/core/device_monitor_win.h b/device/core/device_monitor_win.h
index e8becd7..36600e4 100644
--- a/device/core/device_monitor_win.h
+++ b/device/core/device_monitor_win.h
@@ -8,14 +8,15 @@
 #include <windows.h>
 
 #include "base/observer_list.h"
+#include "device/core/device_core_export.h"
 
 namespace device {
 
 // Use an instance of this class to observe devices being added and removed
 // from the system, matched by device interface GUID.
-class DeviceMonitorWin {
+class DEVICE_CORE_EXPORT DeviceMonitorWin {
  public:
-  class Observer {
+  class DEVICE_CORE_EXPORT Observer {
    public:
     virtual void OnDeviceAdded(const GUID& class_guid,
                                const std::string& device_path);