[Chromecast] Use cast ozone platforms for audio builds

This eliminates need for disable_display logic in a few places:
* logic for when to build Cast Ozone
* logic for --ozone-platform switches

Cast Ozone recently had headless mode added based on --disable-gpu
switch.  Rather than require all audio builds, tests etc to use this
switch, just enable headless mode for DISABLE_DISPLAY builds.

BUG=internal b/27268814

Review URL: https://codereview.chromium.org/1739353002

Cr-Commit-Position: refs/heads/master@{#379413}

5 files changed, 38 insertions, 33 deletions

diff --git a/build/common.gypi b/build/common.gypi
index 5265f00..4b337f9 100644
--- a/build/common.gypi
+++ b/build/common.gypi
@@ -2388,24 +2388,17 @@
         'ozone_platform_headless%': 1,
         'conditions': [
           ['chromecast==1', {
+            'ozone_platform_cast%': 1,
             'conditions': [
-              ['disable_display==0', {
-                # Enable the Cast ozone platform on all A/V Cast builds.
-                'ozone_platform_cast%': 1,
-
-                # For desktop Chromecast builds, override the default "headless"
-                # platform with --ozone-platform=egltest
-                # TODO(slan|halliwell): Make the default platform "cast" on
-                # desktop too.
-                'conditions': [
-                  ['is_cast_desktop_build==1', {
-                    'ozone_platform_egltest%': 1,
-                    'ozone_platform_ozonex%': 1,
-                  }, {
-                    # On device builds, enable "cast" as the default platform.
-                    'ozone_platform%': 'cast',
-                  }],
-                ],
+              # For desktop non-audio Chromecast builds, run with
+              # --ozone-platform=egltest
+              # TODO(slan|halliwell): Make the default platform "cast" on
+              # desktop non-audio builds too.
+              ['is_cast_desktop_build==1 and disable_display==0', {
+                'ozone_platform_egltest%': 1,
+                'ozone_platform_ozonex%': 1,
+              }, {
+                'ozone_platform%': 'cast',
               }],
             ],
           }, {  # chromecast!=1
diff --git a/ui/ozone/ozone.gni b/ui/ozone/ozone.gni
index 31e6dbf..2287c1e 100644
--- a/ui/ozone/ozone.gni
+++ b/ui/ozone/ozone.gni
@@ -37,22 +37,18 @@ declare_args() {
     ozone_platform_headless = true
 
     if (is_chromecast) {
-      if (!disable_display) {
-        # Enable the Cast ozone platform on all A/V Cast builds.
-        ozone_platform_cast = true
+      # Enable the Cast ozone platform on all A/V Cast builds.
+      ozone_platform_cast = true
 
-        # For desktop Chromecast builds, override the default "headless"
-        # platform with --ozone-platform=egltest
-        # TODO(halliwell): Create a libcast_graphics implementation for desktop
-        # using X11, and disable these two platforms. "cast" platform should be
-        # the default on every A/V build.
-        if (is_cast_desktop_build) {
-          ozone_platform_egltest = true
-          ozone_platform_ozonex = true
-        } else {
-          # On device builds, enable "cast" as the default platform.
-          ozone_platform = "cast"
-        }
+      # For visual desktop Chromecast builds, override the default "headless"
+      # platform with --ozone-platform=egltest
+      # TODO(halliwell): Create a libcast_graphics implementation for desktop
+      # using X11, and disable these two platforms.
+      if (is_cast_desktop_build && !disable_display) {
+        ozone_platform_egltest = true
+        ozone_platform_ozonex = true
+      } else {
+        ozone_platform = "cast"
       }
     } else if (is_chromeos) {
       ozone_platform_gbm = true
diff --git a/ui/ozone/platform/cast/BUILD.gn b/ui/ozone/platform/cast/BUILD.gn
index 0a548e4..53de77f 100644
--- a/ui/ozone/platform/cast/BUILD.gn
+++ b/ui/ozone/platform/cast/BUILD.gn
@@ -37,6 +37,10 @@ source_set("cast") {
   # do not want to statically link against EGL library.
   libs = [ "dl" ]
 
+  if (disable_display) {
+    defines = [ "DISABLE_DISPLAY" ]
+  }
+
   deps = [
     "//base",
     "//chromecast/graphics:libcast_graphics_1.0",
diff --git a/ui/ozone/platform/cast/cast.gypi b/ui/ozone/platform/cast/cast.gypi
index ce3a62d..ae875b4 100644
--- a/ui/ozone/platform/cast/cast.gypi
+++ b/ui/ozone/platform/cast/cast.gypi
@@ -30,6 +30,11 @@
       'include_dirs': [
         '<(DEPTH)/third_party/khronos',
       ],
+      'conditions': [
+        ['disable_display==1', {
+          'defines': ['DISABLE_DISPLAY'],
+        }],
+      ],
 
       'sources': [
         'client_native_pixmap_factory_cast.cc',
diff --git a/ui/ozone/platform/cast/ozone_platform_cast.cc b/ui/ozone/platform/cast/ozone_platform_cast.cc
index 5091c93..75e05c3 100644
--- a/ui/ozone/platform/cast/ozone_platform_cast.cc
+++ b/ui/ozone/platform/cast/ozone_platform_cast.cc
@@ -85,8 +85,15 @@ class OzonePlatformCast : public OzonePlatform {
     gpu_platform_support_host_.reset(CreateStubGpuPlatformSupportHost());
 
     // Enable dummy software rendering support if GPU process disabled
+    // or if we're an audio-only build.
     // Note: switch is kDisableGpu from content/public/common/content_switches.h
-    if (base::CommandLine::ForCurrentProcess()->HasSwitch("disable-gpu"))
+    bool enable_dummy_software_rendering = true;
+#if !defined(DISABLE_DISPLAY)
+    enable_dummy_software_rendering =
+        base::CommandLine::ForCurrentProcess()->HasSwitch("disable-gpu");
+#endif
+
+    if (enable_dummy_software_rendering)
       surface_factory_.reset(new SurfaceFactoryCast());
   }
   void InitializeGPU() override {