Add 16-bit support for browser compositor surface

ui/gl/gl_surface_egl.cc

Index: ui/gl/gl_surface_egl.cc
diff --git a/ui/gl/gl_surface_egl.cc b/ui/gl/gl_surface_egl.cc
index b6a7184c129f7e3e18588c69864f775420ab7ae3..35d50a9b5e95a0c0ebee3831428ebfdbd72a2734 100644
--- a/ui/gl/gl_surface_egl.cc
+++ b/ui/gl/gl_surface_egl.cc
@@ -12,6 +12,7 @@
 #include <android/native_window_jni.h>
 #endif
 
+#include "base/android/sys_utils.h"

[kalyank, 2014/01/20 14:48:31]

We could include this only on Android platform.

[kalyank, 2014/01/20 14:49:52]

sorry, ignore this. I was looking at wrong version of the patch.

 #include "base/command_line.h"
 #include "base/debug/trace_event.h"
 #include "base/logging.h"
@@ -137,7 +138,7 @@ bool GLSurfaceEGL::InitializeOneOff() {
 
   // Choose an EGL configuration.
   // On X this is only used for PBuffer surfaces.
-  static const EGLint kConfigAttribs[] = {
+  static EGLint configattribs_8888[] = {

[piman, 2014/01/17 18:20:01]

nit: config_attribs_8888

[sivag, 2014/01/20 14:10:37]

Done.

     EGL_BUFFER_SIZE, 32,
     EGL_ALPHA_SIZE, 8,
     EGL_BLUE_SIZE, 8,
@@ -148,16 +149,39 @@ bool GLSurfaceEGL::InitializeOneOff() {
     EGL_NONE
   };
 
+#if defined(OS_ANDROID)
+  static EGLint configattribs_565[] = {

[piman, 2014/01/17 18:20:01]

nit: config_attribs_565

[sivag, 2014/01/20 14:10:37]

Done.

+    EGL_BUFFER_SIZE, 16,
+    EGL_BLUE_SIZE, 5,
+    EGL_GREEN_SIZE, 6,
+    EGL_RED_SIZE, 5,
+    EGL_RENDERABLE_TYPE, EGL_OPENGL_ES2_BIT,
+    EGL_SURFACE_TYPE, EGL_WINDOW_BIT | EGL_PBUFFER_BIT,
+    EGL_NONE
+  };
+#endif
+
+  EGLint* choose_attributes = 0;
+#if defined(OS_ANDROID)
+  if (base::android::SysUtils::IsLowEndDevice()) {
+    choose_attributes = configattribs_565;
+  } else {
+    choose_attributes = configattribs_8888;
+  }
+#else
+  choose_attributes = configattribs_8888;
+#endif
+
 #if defined(USE_OZONE)
-  const EGLint* config_attribs =
-      surface_factory->GetEGLSurfaceProperties(kConfigAttribs);
+  const EGLint* kConfigAttribs =

[no sievers, 2014/01/17 18:05:30]

nit: Just use |choose_attributes| here and below.
Also |kConfigAttribs| suggests it's constant, although it's really chosen at
runtime.

[sivag, 2014/01/20 14:10:37]

Done.

+      surface_factory->GetEGLSurfaceProperties(choose_attributes);
 #else
-  const EGLint* config_attribs = kConfigAttribs;
+  const EGLint* kConfigAttribs = choose_attributes;
 #endif
 
   EGLint num_configs;
   if (!eglChooseConfig(g_display,
-                       config_attribs,
+                       kConfigAttribs,
                        NULL,
                        0,
                        &num_configs)) {
@@ -171,16 +195,66 @@ bool GLSurfaceEGL::InitializeOneOff() {
     return false;
   }
 
+  EGLConfig* matching_configs = NULL;
+  int config_size = 1;
+
+#if defined(OS_ANDROID)
+  if (base::android::SysUtils::IsLowEndDevice()) {
+    matching_configs = (EGLConfig*)malloc(num_configs * sizeof(EGLConfig));

[no sievers, 2014/01/17 18:05:30]

Instead of malloc/free, you can use:
scoped_ptr<EGLConfig[]> matching_configs(new EGLConfig[num_configs]);

Also put a comment that because of the EGL config sort order, we have to iterate
through all of them (it'll put higher sum(R,G,B) bits first with the above
attribs).

[sivag, 2014/01/20 14:10:37]

Done.

+    config_size = num_configs;
+  } else {
+    matching_configs = &g_config;
+    config_size = 1;
+  }
+#else
+  matching_configs = &g_config;
+  config_size = 1;
+#endif
+
   if (!eglChooseConfig(g_display,
-                       config_attribs,
-                       &g_config,
-                       1,
+                       kConfigAttribs,
+                       matching_configs,
+                       config_size,
                        &num_configs)) {
     LOG(ERROR) << "eglChooseConfig failed with error "
                << GetLastEGLErrorString();
     return false;
   }
 
+#if defined(OS_ANDROID)
+  if (base::android::SysUtils::IsLowEndDevice()) {
+    bool match_found = false;
+    for (int i = 0; i < num_configs; i++)
+    {

[piman, 2014/01/17 18:20:01]

nit: { on previous line

[sivag, 2014/01/20 14:10:37]

Done.

+      EGLBoolean success;
+      EGLint red, green, blue;
+      // Read the relevent attributes of the EGLConfig.
+      success = eglGetConfigAttrib(g_display, matching_configs[i],
+                                   EGL_RED_SIZE, &red);
+      success &= eglGetConfigAttrib(g_display, matching_configs[i],
+                                    EGL_BLUE_SIZE, &blue);
+      success &= eglGetConfigAttrib(g_display, matching_configs[i],
+                                    EGL_GREEN_SIZE, &green);
+      // Check that no error occurred and the attributes match.
+      if ((success == EGL_TRUE) && (red == 5) &&
+          (green == 6) && (blue == 5)) {
+        g_config = matching_configs[i];
+        match_found = true;
+        break;
+      }
+    }
+    if (matching_configs) {
+      free(matching_configs);
+      matching_configs = NULL;
+    }
+    if (!match_found) {
+      LOG(ERROR) << "eglChooseConfig failed with error for lowend device"
+               << GetLastEGLErrorString();
+      return false;

[no sievers, 2014/01/17 18:05:30]

We should fall back to 32bit, since not all drivers might support 565.

[sivag, 2014/01/20 14:10:37]

Done.

+    }
+  }
+#endif
+
   g_egl_extensions = eglQueryString(g_display, EGL_EXTENSIONS);
   g_egl_create_context_robustness_supported =
       HasEGLExtension("EGL_EXT_create_context_robustness");