Backport some work from sample to embedder:

runtime/embedders/android/android_extension.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "embedders/android/android_extension.h"
 
 #include <android/log.h>
 #include <EGL/egl.h>
 #include <GLES2/gl2.h>
 #include <GLES2/gl2ext.h>
 #include <jni.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
 #include "include/dart_api.h"
 #include "embedders/android/log.h"
 
 Dart_Handle HandleError(Dart_Handle handle) {
   if (Dart_IsError(handle)) Dart_PropagateError(handle);
   return handle;
 }
 
 void CheckGLError(const char *function) {
   int error = glGetError();
   if (error != GL_NO_ERROR) {
-    LOGE("ERROR!: %s returns %d", function, error);
+    if (error == GL_INVALID_ENUM) {
+      LOGE("%s: An unacceptable value is given for an enumerated argument.",
+           function);
+    } else if (error == GL_INVALID_VALUE) {
+      LOGE("%s: A numeric argument is out of range.", function);
+    } else if (error == GL_INVALID_OPERATION) {
+      LOGE("%s: The specified operation is not allowed in the current state.",
+           function);
+    } else if (error == GL_INVALID_FRAMEBUFFER_OPERATION) {
+      LOGE("%s: The framebuffer object is not complete.", function);
+    } else if (error == GL_OUT_OF_MEMORY) {
+      LOGE("%s: There is not enough memory left to execute the command.",
+          function);
+    } else {
+      LOGE("ERROR!: %s returns %d", function, error);
+    }
   }
 }
 
-const char* GetStringArg(Dart_NativeArguments arguments, int idx) {
+const char* GetArgAsString(Dart_NativeArguments arguments, int idx) {
   Dart_Handle whatHandle = HandleError(Dart_GetNativeArgument(arguments, idx));
   uint8_t* str;
   intptr_t length;
   HandleError(Dart_StringLength(whatHandle, &length));
   HandleError(Dart_StringToUTF8(whatHandle, &str, &length));
   str[length] = 0;
   return  const_cast<const char*>(reinterpret_cast<char*>(str));
 }
 
+double GetArgAsDouble(Dart_NativeArguments arguments, int index) {
+  Dart_Handle handle = HandleError(Dart_GetNativeArgument(arguments, index));
+  if (Dart_IsDouble(handle)) {
+    double v;
+    HandleError(Dart_DoubleValue(handle, &v));
+    return v;
+  }
+  if (Dart_IsInteger(handle)) {
+    int64_t v;
+    HandleError(Dart_IntegerToInt64(handle, &v));
+    return static_cast<double>(v);
+  }
+  LOGE("Argument at index %d has non-numeric type", index);
+  Dart_ThrowException(Dart_NewStringFromCString("Numeric argument expected."));
+  return 0;
+}
+
+int64_t GetArgAsInt(Dart_NativeArguments arguments, int index) {
+  Dart_Handle handle = HandleError(Dart_GetNativeArgument(arguments, index));
+  if (Dart_IsDouble(handle)) {
+    double v;
+    HandleError(Dart_DoubleValue(handle, &v));
+    return static_cast<int64_t>(v);
+  }
+  if (Dart_IsInteger(handle)) {
+    int64_t v;
+    HandleError(Dart_IntegerToInt64(handle, &v));
+    return v;
+  }
+  LOGE("Argument at index %d has non-numeric type", index);
+  Dart_ThrowException(Dart_NewStringFromCString("Numeric argument expected."));
+  return 0;
+}
+
+bool GetArgAsBool(Dart_NativeArguments arguments, int index) {
+  Dart_Handle handle = HandleError(Dart_GetNativeArgument(arguments, index));
+  if (Dart_IsBoolean(handle)) {
+    bool v;
+    HandleError(Dart_BooleanValue(handle, &v));
+    return v;
+  }
+  LOGI("Argument at index %d has non-Boolean type", index);
+  Dart_ThrowException(Dart_NewStringFromCString("Boolean argument expected."));
+  return false;
+}
+
+GLint* GetArgsAsGLintList(Dart_NativeArguments arguments, int index,
+                          int* len_out) {
+  Dart_Handle argHandle = HandleError(Dart_GetNativeArgument(arguments, index));
+  if (Dart_IsList(argHandle)) {
+    int len;
+    HandleError(Dart_ListLength(argHandle, &len));
+    GLint* list = new GLint[len];
+    for (int i = 0; i < len; i++) {
+      Dart_Handle vHandle = Dart_ListGetAt(argHandle, i);
+      int64_t v;
+      HandleError(Dart_IntegerToInt64(vHandle, &v));
+      list[i] = v;
+    }
+    *len_out = len;
+    return list;
+  }
+  LOGI("Argument at index %d has non-List type", index);
+  Dart_ThrowException(Dart_NewStringFromCString("List argument expected."));
+  return NULL;
+}
+
+GLfloat* GetArgsAsFloatList(Dart_NativeArguments arguments, int index,
+                            int* len_out) {
+  Dart_Handle locationHandle =
+      HandleError(Dart_GetNativeArgument(arguments, 0));
+  int64_t location;
+  HandleError(Dart_IntegerToInt64(locationHandle, &location));
+
+  Dart_Handle argHandle = HandleError(Dart_GetNativeArgument(arguments, 1));
+
+  if (Dart_IsList(argHandle)) {
+    int len;
+    HandleError(Dart_ListLength(argHandle, &len));
+    GLfloat* list = new GLfloat[len];
+    for (int i = 0; i < len; i++) {
+      Dart_Handle vHandle = Dart_ListGetAt(argHandle, i);
+      double v;
+      HandleError(Dart_DoubleValue(vHandle, &v));
+      list[i] = v;
+    }
+    *len_out = len;
+    return list;
+  }
+  LOGI("Argument at index %d has non-List type", index);
+  Dart_ThrowException(Dart_NewStringFromCString("List argument expected."));
+  return NULL;
+}
+
+void SetBoolReturnValue(Dart_NativeArguments arguments, bool b) {
+  Dart_Handle result = HandleError(Dart_NewBoolean(b));
+  Dart_SetReturnValue(arguments, result);
+}
+
+void SetIntReturnValue(Dart_NativeArguments arguments, int v) {
+  Dart_Handle result = HandleError(Dart_NewInteger(v));
+  Dart_SetReturnValue(arguments, result);
+}
+
+void SetStringReturnValue(Dart_NativeArguments arguments, const char* s) {
+  Dart_Handle result = HandleError(Dart_NewStringFromCString(s));
+  Dart_SetReturnValue(arguments, result);
+}
+
 void Log(Dart_NativeArguments arguments) {
   Dart_EnterScope();
-  LOGI(GetStringArg(arguments, 0));
+  LOGI(GetArgAsString(arguments, 0));
+  Dart_ExitScope();
+}
+
+void LogError(Dart_NativeArguments arguments) {
+  Dart_EnterScope();
+  LOGE(GetArgAsString(arguments, 0));
   Dart_ExitScope();
 }
 
 void SystemRand(Dart_NativeArguments arguments) {
   Dart_EnterScope();
-  Dart_Handle result = HandleError(Dart_NewInteger(rand()));
-  Dart_SetReturnValue(arguments, result);
+  SetIntReturnValue(arguments, rand());
   Dart_ExitScope();
 }
 
 void SystemSrand(Dart_NativeArguments arguments) {
   Dart_EnterScope();
   bool success = false;
   Dart_Handle seed_object = HandleError(Dart_GetNativeArgument(arguments, 0));
   if (Dart_IsInteger(seed_object)) {
     bool fits;
     HandleError(Dart_IntegerFitsIntoInt64(seed_object, &fits));
     if (fits) {
       int64_t seed;
       HandleError(Dart_IntegerToInt64(seed_object, &seed));
       srand(static_cast<unsigned>(seed));
       success = true;
     }
   }
-  Dart_SetReturnValue(arguments, HandleError(Dart_NewBoolean(success)));
+  SetBoolReturnValue(arguments, success);
   Dart_ExitScope();
 }
 
 void EGLSwapBuffers(Dart_NativeArguments arguments) {
   LOGI("GLSwapBuffers");
   Dart_EnterScope();
 
   EGLDisplay display = eglGetDisplay(EGL_DEFAULT_DISPLAY);
   EGLSurface surface = eglGetCurrentSurface(EGL_DRAW);
   eglSwapBuffers(display, surface);
 
   CheckGLError("eglSwapBuffers");
   Dart_ExitScope();
 }
 
 void GLAttachShader(Dart_NativeArguments arguments) {
   LOGI("GLAttachShader");
   Dart_EnterScope();
 
-  Dart_Handle programHandle = HandleError(Dart_GetNativeArgument(arguments, 0));
-  int64_t program;
-  HandleError(Dart_IntegerToInt64(programHandle, &program));
-
-  Dart_Handle shaderHandle = HandleError(Dart_GetNativeArgument(arguments, 1));
-  int64_t shader;
-  HandleError(Dart_IntegerToInt64(shaderHandle, &shader));
+  int64_t program = GetArgAsInt(arguments, 0);
+  int64_t shader = GetArgAsInt(arguments, 1);
 
   glAttachShader(program, shader);
   CheckGLError("glAttachShader");
   Dart_ExitScope();
 }
 
 void GLBindBuffer(Dart_NativeArguments arguments) {
   LOGI("GLBindBuffer");
   Dart_EnterScope();
 
-  Dart_Handle targetHandle = HandleError(Dart_GetNativeArgument(arguments, 0));
-  int64_t target;
-  HandleError(Dart_IntegerToInt64(targetHandle, &target));
-
-  Dart_Handle bufferHandle = HandleError(Dart_GetNativeArgument(arguments, 1));
-  int64_t buffer;
-  HandleError(Dart_IntegerToInt64(bufferHandle, &buffer));
+  int64_t target = GetArgAsInt(arguments, 0);
+  int64_t buffer = GetArgAsInt(arguments, 1);
 
   glBindBuffer(target, buffer);
   CheckGLError("glBindBuffer");
   Dart_ExitScope();
 }
 
 void GLBufferData(Dart_NativeArguments arguments) {
   LOGI("GLBufferData");
   Dart_EnterScope();
 
-  Dart_Handle targetHandle = HandleError(Dart_GetNativeArgument(arguments, 0));
-  int64_t target;
-  HandleError(Dart_IntegerToInt64(targetHandle, &target));
+  int64_t target = GetArgAsInt(arguments, 0);
 
   Dart_Handle dataHandle = HandleError(Dart_GetNativeArgument(arguments, 1));
   intptr_t size;
   HandleError(Dart_ListLength(dataHandle, &size));
 
   LOGI("Size: %d", size);
 
   // TODO(vsm): No guarantee that this is a float!
-  float* data = reinterpret_cast<float*>(malloc(size * sizeof(float)));
+  float* data = new float[size];
   for (int i = 0; i < size; i++) {
     Dart_Handle elemHandle = HandleError(Dart_ListGetAt(dataHandle, i));
     double value;
     Dart_DoubleValue(elemHandle, &value);
     data[i] = static_cast<float>(value);
     LOGI("Value[%d]: %f", i, data[i]);
   }
 
   Dart_Handle usageHandle = HandleError(Dart_GetNativeArgument(arguments, 2));
   int64_t usage;
   HandleError(Dart_IntegerToInt64(usageHandle, &usage));
 
-  glBufferData(target, size * sizeof(float), data, usage);
+  glBufferData(target, size * sizeof(data[0]), data, usage);
   CheckGLError("glBufferData");
-  free(data);
+  delete[] data;
   Dart_ExitScope();
 }
 
 void GLCompileShader(Dart_NativeArguments arguments) {
+  LOGI("GLCompileShader");
   Dart_EnterScope();
-
-  Dart_Handle shaderHandle = HandleError(Dart_GetNativeArgument(arguments, 0));
-  int64_t shader;
-  HandleError(Dart_IntegerToInt64(shaderHandle, &shader));
-
-  LOGI("GLCompileShader");
+  int64_t shader = GetArgAsInt(arguments, 0);
   glCompileShader(shader);
   CheckGLError("glCompileShader");
   Dart_ExitScope();
 }
 
 void GLCreateBuffer(Dart_NativeArguments arguments) {
   LOGI("GLCreateBuffer");
   Dart_EnterScope();
   GLuint buffer;
-
   glGenBuffers(1, &buffer);
   CheckGLError("glGenBuffers");
-  Dart_Handle result = HandleError(Dart_NewInteger(buffer));
-  Dart_SetReturnValue(arguments, result);
+  SetIntReturnValue(arguments, buffer);
   Dart_ExitScope();
 }
 
 void GLCreateProgram(Dart_NativeArguments arguments) {
   LOGI("GLCreateProgram");
   Dart_EnterScope();
-
   int64_t program = glCreateProgram();
   CheckGLError("glCreateProgram");
-  Dart_Handle result = HandleError(Dart_NewInteger(program));
-  Dart_SetReturnValue(arguments, result);
+  SetIntReturnValue(arguments, program);
   Dart_ExitScope();
 }
 
 void GLCreateShader(Dart_NativeArguments arguments) {
+  LOGI("GLCreateShader");
   Dart_EnterScope();
-
-  Dart_Handle typeHandle = HandleError(Dart_GetNativeArgument(arguments, 0));
-  int64_t type;
-  HandleError(Dart_IntegerToInt64(typeHandle, &type));
-
+  int64_t type = GetArgAsInt(arguments, 0);
   int64_t shader = glCreateShader((GLenum)type);
-  LOGI("GLCreateShader");
   CheckGLError("glCreateShader");
-  Dart_Handle result = HandleError(Dart_NewInteger(shader));
-  Dart_SetReturnValue(arguments, result);
+  SetIntReturnValue(arguments, shader);
   Dart_ExitScope();
 }
 
 void GLDrawArrays(Dart_NativeArguments arguments) {
   LOGI("GLDrawArrays");
   Dart_EnterScope();
 
-  Dart_Handle modeHandle = HandleError(Dart_GetNativeArgument(arguments, 0));
-  int64_t mode;
-  HandleError(Dart_IntegerToInt64(modeHandle, &mode));
-
-  Dart_Handle firstHandle = HandleError(Dart_GetNativeArgument(arguments, 1));
-  int64_t first;
-  HandleError(Dart_IntegerToInt64(firstHandle, &first));
-
-  Dart_Handle countHandle = HandleError(Dart_GetNativeArgument(arguments, 2));
-  int64_t count;
-  HandleError(Dart_IntegerToInt64(countHandle, &count));
+  int64_t mode = GetArgAsInt(arguments, 0);
+  int64_t first = GetArgAsInt(arguments, 1);
+  int64_t count = GetArgAsInt(arguments, 2);
 
   glDrawArrays(mode, first, count);
   CheckGLError("glDrawArrays");
   Dart_ExitScope();
 }
 
 void GLEnableVertexAttribArray(Dart_NativeArguments arguments) {
   LOGI("GLEnableVertexAttribArray");
   Dart_EnterScope();
 
-  Dart_Handle locationHandle =
-      HandleError(Dart_GetNativeArgument(arguments, 0));
-  int64_t location;
-  HandleError(Dart_IntegerToInt64(locationHandle, &location));
+  int64_t location = GetArgAsInt(arguments, 0);
 
   glEnableVertexAttribArray(location);
   CheckGLError("glEnableVertexAttribArray");
   Dart_ExitScope();
 }
 
 void GLGetAttribLocation(Dart_NativeArguments arguments) {
   LOGI("GLGetAttribLocation");
   Dart_EnterScope();
 
-  Dart_Handle programHandle = HandleError(Dart_GetNativeArgument(arguments, 0));
-  int64_t program;
-  HandleError(Dart_IntegerToInt64(programHandle, &program));
+  int64_t program = GetArgAsInt(arguments, 0);
 
   Dart_Handle nameHandle = HandleError(Dart_GetNativeArgument(arguments, 1));
   intptr_t length;
   HandleError(Dart_StringLength(nameHandle, &length));
   uint8_t* str;
   HandleError(Dart_StringToUTF8(nameHandle, &str, &length));
   str[length] = 0;
 
   int64_t location = glGetAttribLocation(program,
       const_cast<const GLchar*>(reinterpret_cast<GLchar*>(str)));
   CheckGLError("glGetAttribLocation");
-  Dart_Handle result = HandleError(Dart_NewInteger(location));
-  Dart_SetReturnValue(arguments, result);
+  SetIntReturnValue(arguments, location);
   Dart_ExitScope();
 }
 
 void GLGetError(Dart_NativeArguments arguments) {
   LOGI("GLGetError");
   Dart_EnterScope();
-
-  int64_t error = glGetError();
-  Dart_Handle result = HandleError(Dart_NewInteger(error));
-  Dart_SetReturnValue(arguments, result);
+  SetIntReturnValue(arguments, glGetError());
   Dart_ExitScope();
 }
 
 void GLGetProgramParameter(Dart_NativeArguments arguments) {
   LOGI("GLGetProgramParameter");
   Dart_EnterScope();
 
-  Dart_Handle programHandle = HandleError(Dart_GetNativeArgument(arguments, 0));
-  int64_t program;
-  HandleError(Dart_IntegerToInt64(programHandle, &program));
-
-  Dart_Handle paramHandle = HandleError(Dart_GetNativeArgument(arguments, 1));
-  int64_t param;
-  HandleError(Dart_IntegerToInt64(paramHandle, &param));
+  int64_t program = GetArgAsInt(arguments, 0);
+  int64_t param = GetArgAsInt(arguments, 1);
 
   GLint value = -1;
   glGetProgramiv(program, param, &value);
   CheckGLError("glGetProgramiv");
 
-  Dart_Handle result = HandleError(Dart_NewInteger(value));
-  Dart_SetReturnValue(arguments, result);
+  SetIntReturnValue(arguments, value);
   Dart_ExitScope();
 }
 
 void GLGetShaderParameter(Dart_NativeArguments arguments) {
   LOGI("GLGetShaderParameter");
   Dart_EnterScope();
 
-  Dart_Handle shaderHandle = HandleError(Dart_GetNativeArgument(arguments, 0));
-  int64_t shader;
-  HandleError(Dart_IntegerToInt64(shaderHandle, &shader));
-
-  Dart_Handle paramHandle = HandleError(Dart_GetNativeArgument(arguments, 1));
-  int64_t param;
-  HandleError(Dart_IntegerToInt64(paramHandle, &param));
+  int64_t shader = GetArgAsInt(arguments, 0);
+  int64_t param = GetArgAsInt(arguments, 1);
 
   GLint value = -1;
   glGetShaderiv((GLuint)shader, (GLenum)param, &value);
   CheckGLError("glGetShaderiv");
 
-  Dart_Handle result = HandleError(Dart_NewInteger(value));
-  Dart_SetReturnValue(arguments, result);
+  SetIntReturnValue(arguments, value);
   Dart_ExitScope();
 }
 
 void GLGetShaderInfoLog(Dart_NativeArguments arguments) {
   LOGI("GLGetShaderInfoLog");
   Dart_EnterScope();
 
-  Dart_Handle shaderHandle = HandleError(Dart_GetNativeArgument(arguments, 0));
-  int64_t shader;
-  HandleError(Dart_IntegerToInt64(shaderHandle, &shader));
+  int64_t shader = GetArgAsInt(arguments, 0);
 
   GLint infoLogLength = 0;
   glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &infoLogLength);
 
   GLchar* strInfoLog = new GLchar[infoLogLength + 1];
   glGetShaderInfoLog(shader, infoLogLength, NULL, strInfoLog);
   strInfoLog[infoLogLength] = 0;
 
-  Dart_Handle result = HandleError(Dart_NewStringFromCString(strInfoLog));
-  Dart_SetReturnValue(arguments, result);
+  SetStringReturnValue(arguments, strInfoLog);
   Dart_ExitScope();
   delete[] strInfoLog;
 }
 
 void GLGetProgramInfoLog(Dart_NativeArguments arguments) {
   LOGI("GLGetProgramInfoLog");
   Dart_EnterScope();
 
-  Dart_Handle programHandle = HandleError(Dart_GetNativeArgument(arguments, 0));
-  int64_t program;
-  HandleError(Dart_IntegerToInt64(programHandle, &program));
+  int64_t program = GetArgAsInt(arguments, 0);
 
   GLint infoLogLength;
   glGetProgramiv(program, GL_INFO_LOG_LENGTH, &infoLogLength);
 
   GLchar* strInfoLog = new GLchar[infoLogLength + 1];
   glGetProgramInfoLog(program, infoLogLength, NULL, strInfoLog);
   strInfoLog[infoLogLength] = 0;
 
-  Dart_Handle result = HandleError(Dart_NewStringFromCString(strInfoLog));
-  Dart_SetReturnValue(arguments, result);
+  SetStringReturnValue(arguments, strInfoLog);
   Dart_ExitScope();
   delete[] strInfoLog;
 }
 
 void GLGetUniformLocation(Dart_NativeArguments arguments) {
   LOGI("GLGetUniformLocation");
   Dart_EnterScope();
 
-  Dart_Handle programHandle = HandleError(Dart_GetNativeArgument(arguments, 0));
-  int64_t program;
-  HandleError(Dart_IntegerToInt64(programHandle, &program));
+  int64_t program = GetArgAsInt(arguments, 0);
+
 
   Dart_Handle nameHandle = HandleError(Dart_GetNativeArgument(arguments, 1));
   intptr_t length;
   HandleError(Dart_StringLength(nameHandle, &length));
   uint8_t* str;
   HandleError(Dart_StringToUTF8(nameHandle, &str, &length));
   str[length] = 0;
 
   int64_t location = glGetUniformLocation(program,
       const_cast<const GLchar*>(reinterpret_cast<GLchar*>(str)));
   CheckGLError("glGetUniformLocation");
-  Dart_Handle result = HandleError(Dart_NewInteger(location));
-  Dart_SetReturnValue(arguments, result);
+  SetIntReturnValue(arguments, location);
   Dart_ExitScope();
 }
 
 void GLLinkProgram(Dart_NativeArguments arguments) {
   LOGI("GLLinkProgram");
   Dart_EnterScope();
-
-  Dart_Handle programHandle = HandleError(Dart_GetNativeArgument(arguments, 0));
-  int64_t program;
-  HandleError(Dart_IntegerToInt64(programHandle, &program));
-
+  int64_t program = GetArgAsInt(arguments, 0);
   glLinkProgram(program);
   CheckGLError("glLinkProgram");
   Dart_ExitScope();
 }
 
 void GLShaderSource(Dart_NativeArguments arguments) {
   LOGI("GLShaderSource");
   Dart_EnterScope();
 
-  Dart_Handle shaderHandle = HandleError(Dart_GetNativeArgument(arguments, 0));
-  int64_t shader;
-  HandleError(Dart_IntegerToInt64(shaderHandle, &shader));
+  int64_t shader = GetArgAsInt(arguments, 0);
 
   Dart_Handle sourceHandle = HandleError(Dart_GetNativeArgument(arguments, 1));
   intptr_t length[1];
   HandleError(Dart_StringLength(sourceHandle, length));
   LOGI("Source length is %d", length[0]);
   uint8_t* str[1];
   HandleError(Dart_StringToUTF8(sourceHandle, &str[0], length));
   LOGI("Converted length is %d", length[0]);
   str[0][*length] = 0;
 
   const GLchar* source =
       const_cast<const GLchar*>(reinterpret_cast<GLchar*>(str[0]));
   LOGI("Source: %s", source);
   glShaderSource(shader, 1,
       const_cast<const GLchar**>(reinterpret_cast<GLchar**>(str)), NULL);
   CheckGLError("glShaderSource");
   Dart_ExitScope();
 }
 
 void GLUseProgram(Dart_NativeArguments arguments) {
   LOGI("GLUseProgram");
   Dart_EnterScope();
-
-  Dart_Handle programHandle = HandleError(Dart_GetNativeArgument(arguments, 0));
-  int64_t program;
-  HandleError(Dart_IntegerToInt64(programHandle, &program));
-
+  int64_t program = GetArgAsInt(arguments, 0);
   glUseProgram(program);
   CheckGLError("glUseProgram");
   Dart_ExitScope();
 }
 
 void GLUniform1i(Dart_NativeArguments arguments) {
   LOGI("GLUniform1i");
   Dart_EnterScope();
-
-  Dart_Handle locationHandle =
-      HandleError(Dart_GetNativeArgument(arguments, 0));
-  int64_t location;
-  HandleError(Dart_IntegerToInt64(locationHandle, &location));
-
-  Dart_Handle v0Handle = HandleError(Dart_GetNativeArgument(arguments, 1));
-  int64_t v0;
-  HandleError(Dart_IntegerToInt64(v0Handle, &v0));
-
+  int64_t location = GetArgAsInt(arguments, 0);
+  int64_t v0 = GetArgAsInt(arguments, 1);
   glUniform1i(location, v0);
   CheckGLError("glUniform1i");
   Dart_ExitScope();
 }
 
 void GLUniform2i(Dart_NativeArguments arguments) {
   LOGI("GLUniform2i");
   Dart_EnterScope();
-
-  Dart_Handle locationHandle =
-      HandleError(Dart_GetNativeArgument(arguments, 0));
-  int64_t location;
-  HandleError(Dart_IntegerToInt64(locationHandle, &location));
-
-  Dart_Handle v0Handle = HandleError(Dart_GetNativeArgument(arguments, 1));
-  int64_t v0;
-  HandleError(Dart_IntegerToInt64(v0Handle, &v0));
-
-  Dart_Handle v1Handle = HandleError(Dart_GetNativeArgument(arguments, 2));
-  int64_t v1;
-  HandleError(Dart_IntegerToInt64(v1Handle, &v1));
-
+  int64_t location = GetArgAsInt(arguments, 0);
+  int64_t v0 = GetArgAsInt(arguments, 1);
+  int64_t v1 = GetArgAsInt(arguments, 2);
   glUniform2i(location, v0, v1);
   CheckGLError("glUniform2i");
   Dart_ExitScope();
 }
 
 void GLUniform3i(Dart_NativeArguments arguments) {
   LOGI("GLUniform3i");
   Dart_EnterScope();
-
-  Dart_Handle locationHandle =
-      HandleError(Dart_GetNativeArgument(arguments, 0));
-  int64_t location;
-  HandleError(Dart_IntegerToInt64(locationHandle, &location));
-
-  Dart_Handle v0Handle = HandleError(Dart_GetNativeArgument(arguments, 1));
-  int64_t v0;
-  HandleError(Dart_IntegerToInt64(v0Handle, &v0));
-
-  Dart_Handle v1Handle = HandleError(Dart_GetNativeArgument(arguments, 2));
-  int64_t v1;
-  HandleError(Dart_IntegerToInt64(v1Handle, &v1));
-
-  Dart_Handle v2Handle = HandleError(Dart_GetNativeArgument(arguments, 3));
-  int64_t v2;
-  HandleError(Dart_IntegerToInt64(v2Handle, &v2));
-
+  int64_t location = GetArgAsInt(arguments, 0);
+  int64_t v0 = GetArgAsInt(arguments, 1);
+  int64_t v1 = GetArgAsInt(arguments, 2);
+  int64_t v2 = GetArgAsInt(arguments, 3);
   glUniform3i(location, v0, v1, v2);
   CheckGLError("glUniform3i");
   Dart_ExitScope();
 }
 
 void GLUniform4i(Dart_NativeArguments arguments) {
   LOGI("GLUniform4i");
   Dart_EnterScope();
-
-  Dart_Handle locationHandle =
-      HandleError(Dart_GetNativeArgument(arguments, 0));
-  int64_t location;
-  HandleError(Dart_IntegerToInt64(locationHandle, &location));
-
-  Dart_Handle v0Handle = HandleError(Dart_GetNativeArgument(arguments, 1));
-  int64_t v0;
-  HandleError(Dart_IntegerToInt64(v0Handle, &v0));
-
-  Dart_Handle v1Handle = HandleError(Dart_GetNativeArgument(arguments, 2));
-  int64_t v1;
-  HandleError(Dart_IntegerToInt64(v1Handle, &v1));
-
-  Dart_Handle v2Handle = HandleError(Dart_GetNativeArgument(arguments, 3));
-  int64_t v2;
-  HandleError(Dart_IntegerToInt64(v2Handle, &v2));
-
-  Dart_Handle v3Handle = HandleError(Dart_GetNativeArgument(arguments, 4));
-  int64_t v3;
-  HandleError(Dart_IntegerToInt64(v3Handle, &v3));
-
+  int64_t location = GetArgAsInt(arguments, 0);
+  int64_t v0 = GetArgAsInt(arguments, 1);
+  int64_t v1 = GetArgAsInt(arguments, 2);
+  int64_t v2 = GetArgAsInt(arguments, 3);
+  int64_t v3 = GetArgAsInt(arguments, 4);
   glUniform4i(location, v0, v1, v2, v3);
   CheckGLError("glUniform4i");
   Dart_ExitScope();
 }
 
 void GLUniform1f(Dart_NativeArguments arguments) {
   LOGI("GLUniform1f");
   Dart_EnterScope();
-
-  Dart_Handle locationHandle =
-      HandleError(Dart_GetNativeArgument(arguments, 0));
-  int64_t location;
-  HandleError(Dart_IntegerToInt64(locationHandle, &location));
-
-  Dart_Handle v0Handle = HandleError(Dart_GetNativeArgument(arguments, 1));
-  double v0;
-  HandleError(Dart_DoubleValue(v0Handle, &v0));
-
+  int64_t location = GetArgAsInt(arguments, 0);
+  double v0 = GetArgAsDouble(arguments, 1);
   glUniform1f(location, v0);
   CheckGLError("glUniform1f");
   Dart_ExitScope();
 }
 
 void GLUniform2f(Dart_NativeArguments arguments) {
   LOGI("GLUniform2f");
   Dart_EnterScope();
-
-  Dart_Handle locationHandle =
-      HandleError(Dart_GetNativeArgument(arguments, 0));
-  int64_t location;
-  HandleError(Dart_IntegerToInt64(locationHandle, &location));
-
-  Dart_Handle v0Handle = HandleError(Dart_GetNativeArgument(arguments, 1));
-  double v0;
-  HandleError(Dart_DoubleValue(v0Handle, &v0));
-
-  Dart_Handle v1Handle = HandleError(Dart_GetNativeArgument(arguments, 2));
-  double v1;
-  HandleError(Dart_DoubleValue(v1Handle, &v1));
-
+  int64_t location = GetArgAsInt(arguments, 0);
+  double v0 = GetArgAsDouble(arguments, 1);
+  double v1 = GetArgAsDouble(arguments, 2);
   glUniform2f(location, v0, v1);
   CheckGLError("glUniform2f");
   Dart_ExitScope();
 }
 
 void GLUniform3f(Dart_NativeArguments arguments) {
   LOGI("GLUniform3f");
   Dart_EnterScope();
-
-  Dart_Handle locationHandle =
-      HandleError(Dart_GetNativeArgument(arguments, 0));
-  int64_t location;
-  HandleError(Dart_IntegerToInt64(locationHandle, &location));
-
-  Dart_Handle v0Handle = HandleError(Dart_GetNativeArgument(arguments, 1));
-  double v0;
-  HandleError(Dart_DoubleValue(v0Handle, &v0));
-
-  Dart_Handle v1Handle = HandleError(Dart_GetNativeArgument(arguments, 2));
-  double v1;
-  HandleError(Dart_DoubleValue(v1Handle, &v1));
-
-  Dart_Handle v2Handle = HandleError(Dart_GetNativeArgument(arguments, 3));
-  double v2;
-  HandleError(Dart_DoubleValue(v2Handle, &v2));
-
+  int64_t location = GetArgAsInt(arguments, 0);
+  double v0 = GetArgAsDouble(arguments, 1);
+  double v1 = GetArgAsDouble(arguments, 2);
+  double v2 = GetArgAsDouble(arguments, 3);
   glUniform3f(location, v0, v1, v2);
   CheckGLError("glUniform3f");
   Dart_ExitScope();
 }
 
 void GLUniform4f(Dart_NativeArguments arguments) {
   LOGI("GLUniform4f");
   Dart_EnterScope();
-
-  Dart_Handle locationHandle =
-      HandleError(Dart_GetNativeArgument(arguments, 0));
-  int64_t location;
-  HandleError(Dart_IntegerToInt64(locationHandle, &location));
-
-  Dart_Handle v0Handle = HandleError(Dart_GetNativeArgument(arguments, 1));
-  double v0;
-  HandleError(Dart_DoubleValue(v0Handle, &v0));
-
-  Dart_Handle v1Handle = HandleError(Dart_GetNativeArgument(arguments, 2));
-  double v1;
-  HandleError(Dart_DoubleValue(v1Handle, &v1));
-
-  Dart_Handle v2Handle = HandleError(Dart_GetNativeArgument(arguments, 3));
-  double v2;
-  HandleError(Dart_DoubleValue(v2Handle, &v2));
-
-  Dart_Handle v3Handle = HandleError(Dart_GetNativeArgument(arguments, 4));
-  double v3;
-  HandleError(Dart_DoubleValue(v3Handle, &v3));
-
+  int64_t location = GetArgAsInt(arguments, 0);
+  double v0 = GetArgAsDouble(arguments, 1);
+  double v1 = GetArgAsDouble(arguments, 2);
+  double v2 = GetArgAsDouble(arguments, 3);
+  double v3 = GetArgAsDouble(arguments, 4);
   glUniform4f(location, v0, v1, v2, v3);
   CheckGLError("glUniform4f");
   Dart_ExitScope();
 }
 
 void GLUniform1iv(Dart_NativeArguments arguments) {
   LOGI("GLUniform1iv");
   Dart_EnterScope();
-
-  Dart_Handle locationHandle =
-      HandleError(Dart_GetNativeArgument(arguments, 0));
-  int64_t location;
-  HandleError(Dart_IntegerToInt64(locationHandle, &location));
-
-  Dart_Handle argHandle = HandleError(Dart_GetNativeArgument(arguments, 1));
-
-  if (Dart_IsList(argHandle)) {
-    int len;
-    HandleError(Dart_ListLength(argHandle, &len));
-    GLint* list = new GLint[len];
-    for (int i = 0; i < len; i++) {
-      Dart_Handle vHandle = Dart_ListGetAt(argHandle, i);
-      int64_t v;
-      HandleError(Dart_IntegerToInt64(vHandle, &v));
-      list[i] = v;
-    }
+  int64_t location = GetArgAsInt(arguments, 0);
+  int len;
+  GLint* list = GetArgsAsGLintList(arguments, 1, &len);
+  if (list != NULL) {
     glUniform1iv(location, len, list);
     delete [] list;
     CheckGLError("glUniform1iv");
   }
   Dart_ExitScope();
 }
 
 void GLUniform2iv(Dart_NativeArguments arguments) {
   LOGI("GLUniform2iv");
   Dart_EnterScope();
-
-  Dart_Handle locationHandle =
-      HandleError(Dart_GetNativeArgument(arguments, 0));
-  int64_t location;
-  HandleError(Dart_IntegerToInt64(locationHandle, &location));
-
-  Dart_Handle argHandle = HandleError(Dart_GetNativeArgument(arguments, 1));
-
-  if (Dart_IsList(argHandle)) {
-    int len;
-    HandleError(Dart_ListLength(argHandle, &len));
-    GLint* list = new GLint[len];
-    for (int i = 0; i < len; i++) {
-      Dart_Handle vHandle = Dart_ListGetAt(argHandle, i);
-      int64_t v;
-      HandleError(Dart_IntegerToInt64(vHandle, &v));
-      list[i] = v;
-    }
+  int64_t location = GetArgAsInt(arguments, 0);
+  int len;
+  GLint* list = GetArgsAsGLintList(arguments, 1, &len);
+  if (list != NULL) {
     glUniform2iv(location, len / 2, list);
     delete [] list;
     CheckGLError("glUniform2iv");
   }
   Dart_ExitScope();
 }
 
 void GLUniform3iv(Dart_NativeArguments arguments) {
   LOGI("GLUniform3iv");
   Dart_EnterScope();
-
-  Dart_Handle locationHandle =
-      HandleError(Dart_GetNativeArgument(arguments, 0));
-  int64_t location;
-  HandleError(Dart_IntegerToInt64(locationHandle, &location));
-
-  Dart_Handle argHandle = HandleError(Dart_GetNativeArgument(arguments, 1));
-
-  if (Dart_IsList(argHandle)) {
-    int len;
-    HandleError(Dart_ListLength(argHandle, &len));
-    GLint* list = new GLint[len];
-    for (int i = 0; i < len; i++) {
-      Dart_Handle vHandle = Dart_ListGetAt(argHandle, i);
-      int64_t v;
-      HandleError(Dart_IntegerToInt64(vHandle, &v));
-      list[i] = v;
-    }
+  int64_t location = GetArgAsInt(arguments, 0);
+  int len;
+  GLint* list = GetArgsAsGLintList(arguments, 1, &len);
+  if (list != NULL) {
     glUniform3iv(location, len / 3, list);
     delete [] list;
     CheckGLError("glUniform3iv");
   }
   Dart_ExitScope();
 }
 
 void GLUniform4iv(Dart_NativeArguments arguments) {
   LOGI("GLUniform4iv");
   Dart_EnterScope();
-
-  Dart_Handle locationHandle =
-      HandleError(Dart_GetNativeArgument(arguments, 0));
-  int64_t location;
-  HandleError(Dart_IntegerToInt64(locationHandle, &location));
-
-  Dart_Handle argHandle = HandleError(Dart_GetNativeArgument(arguments, 1));
-
-  if (Dart_IsList(argHandle)) {
-    int len;
-    HandleError(Dart_ListLength(argHandle, &len));
-    GLint* list = new GLint[len];
-    for (int i = 0; i < len; i++) {
-      Dart_Handle vHandle = Dart_ListGetAt(argHandle, i);
-      int64_t v;
-      HandleError(Dart_IntegerToInt64(vHandle, &v));
-      list[i] = v;
-    }
+  int64_t location = GetArgAsInt(arguments, 0);
+  int len;
+  GLint* list = GetArgsAsGLintList(arguments, 1, &len);
+  if (list != NULL) {
     glUniform1iv(location, len / 4, list);
     delete [] list;
     CheckGLError("glUniform4iv");
   }
   Dart_ExitScope();
 }
 
 void GLUniform1fv(Dart_NativeArguments arguments) {
   LOGI("GLUniform1fv");
   Dart_EnterScope();
-
-  Dart_Handle locationHandle =
-      HandleError(Dart_GetNativeArgument(arguments, 0));
-  int64_t location;
-  HandleError(Dart_IntegerToInt64(locationHandle, &location));
-
-  Dart_Handle argHandle = HandleError(Dart_GetNativeArgument(arguments, 1));
-
-  if (Dart_IsList(argHandle)) {
-    int len;
-    HandleError(Dart_ListLength(argHandle, &len));
-    GLfloat* list = new GLfloat[len];
-    for (int i = 0; i < len; i++) {
-      Dart_Handle vHandle = Dart_ListGetAt(argHandle, i);
-      double v;
-      HandleError(Dart_DoubleValue(vHandle, &v));
-      list[i] = v;
-    }
+  int64_t location = GetArgAsInt(arguments, 0);
+  int len;
+  GLfloat* list = GetArgsAsFloatList(arguments, 1, &len);
+  if (list != NULL) {
     glUniform1fv(location, len, list);
     delete [] list;
     CheckGLError("glUniform1fv");
   }
   Dart_ExitScope();
 }
 
 void GLUniform2fv(Dart_NativeArguments arguments) {
   LOGI("GLUniform2fv");
   Dart_EnterScope();
-
-  Dart_Handle locationHandle =
-      HandleError(Dart_GetNativeArgument(arguments, 0));
-  int64_t location;
-  HandleError(Dart_IntegerToInt64(locationHandle, &location));
-
-  Dart_Handle argHandle = HandleError(Dart_GetNativeArgument(arguments, 1));
-
-  if (Dart_IsList(argHandle)) {
-    int len;
-    HandleError(Dart_ListLength(argHandle, &len));
-    GLfloat* list = new GLfloat[len];
-    for (int i = 0; i < len; i++) {
-      Dart_Handle vHandle = Dart_ListGetAt(argHandle, i);
-      double v;
-      HandleError(Dart_DoubleValue(vHandle, &v));
-      list[i] = v;
-    }
+  int64_t location = GetArgAsInt(arguments, 0);
+  int len;
+  GLfloat* list = GetArgsAsFloatList(arguments, 1, &len);
+  if (list != NULL) {
     glUniform2fv(location, len / 2, list);
     delete [] list;
     CheckGLError("glUniform2fv");
   }
   Dart_ExitScope();
 }
 
 void GLUniform3fv(Dart_NativeArguments arguments) {
   LOGI("GLUniform3fv");
   Dart_EnterScope();
-
-  Dart_Handle locationHandle =
-      HandleError(Dart_GetNativeArgument(arguments, 0));
-  int64_t location;
-  HandleError(Dart_IntegerToInt64(locationHandle, &location));
-
-  Dart_Handle argHandle = HandleError(Dart_GetNativeArgument(arguments, 1));
-
-  if (Dart_IsList(argHandle)) {
-    int len;
-    HandleError(Dart_ListLength(argHandle, &len));
-    GLfloat* list = new GLfloat[len];
-    for (int i = 0; i < len; i++) {
-      Dart_Handle vHandle = Dart_ListGetAt(argHandle, i);
-      double v;
-      HandleError(Dart_DoubleValue(vHandle, &v));
-      list[i] = v;
-    }
+  int64_t location = GetArgAsInt(arguments, 0);
+  int len;
+  GLfloat* list = GetArgsAsFloatList(arguments, 1, &len);
+  if (list != NULL) {
     glUniform3fv(location, len / 3, list);
     delete [] list;
     CheckGLError("glUniform3fv");
   }
   Dart_ExitScope();
 }
 
 void GLUniform4fv(Dart_NativeArguments arguments) {
   LOGI("In GLUniform4fv");
   Dart_EnterScope();
-
-  Dart_Handle locationHandle =
-      HandleError(Dart_GetNativeArgument(arguments, 0));
-  int64_t location;
-  HandleError(Dart_IntegerToInt64(locationHandle, &location));
-
-  Dart_Handle argHandle = HandleError(Dart_GetNativeArgument(arguments, 1));
-
-  if (Dart_IsList(argHandle)) {
-    int len;
-    HandleError(Dart_ListLength(argHandle, &len));
-    GLfloat* list = new GLfloat[len];
-    for (int i = 0; i < len; i++) {
-      Dart_Handle vHandle = Dart_ListGetAt(argHandle, i);
-      double v;
-      HandleError(Dart_DoubleValue(vHandle, &v));
-      list[i] = v;
-    }
+  int64_t location = GetArgAsInt(arguments, 0);
+  int len;
+  GLfloat* list = GetArgsAsFloatList(arguments, 1, &len);
+  if (list != NULL) {
     glUniform4fv(location, len / 4, list);
     delete [] list;
     CheckGLError("glUniform4fv");
   }
   Dart_ExitScope();
 }
 
 void GLViewport(Dart_NativeArguments arguments) {
   LOGI("GLViewport");
   Dart_EnterScope();
-
-  Dart_Handle xHandle = HandleError(Dart_GetNativeArgument(arguments, 0));
-  int64_t x;
-  HandleError(Dart_IntegerToInt64(xHandle, &x));
-
-  Dart_Handle yHandle = HandleError(Dart_GetNativeArgument(arguments, 1));
-  int64_t y;
-  HandleError(Dart_IntegerToInt64(yHandle, &y));
-
-  Dart_Handle widthHandle = HandleError(Dart_GetNativeArgument(arguments, 2));
-  int64_t width;
-  HandleError(Dart_IntegerToInt64(widthHandle, &width));
-
-  Dart_Handle heightHandle = HandleError(Dart_GetNativeArgument(arguments, 3));
-  int64_t height;
-  HandleError(Dart_IntegerToInt64(heightHandle, &height));
-
-  LOGI("Dimensions: [%d, %d, %d, %d]",
-       static_cast<int>(x),
-       static_cast<int>(y),
-       static_cast<int>(width),
-       static_cast<int>(height));
-
+  int64_t x = GetArgAsInt(arguments, 0);
+  int64_t y = GetArgAsInt(arguments, 1);
+  int64_t width = GetArgAsInt(arguments, 2);
+  int64_t height = GetArgAsInt(arguments, 3);
   glViewport(x, y, width, height);
   CheckGLError("glViewPort");
   Dart_ExitScope();
 }
 
 void GLVertexAttribPointer(Dart_NativeArguments arguments) {
   LOGI("GLVertexAttribPointer");
   Dart_EnterScope();
-
-  Dart_Handle indexHandle = HandleError(Dart_GetNativeArgument(arguments, 0));
-  int64_t index;
-  HandleError(Dart_IntegerToInt64(indexHandle, &index));
-
-  Dart_Handle sizeHandle = HandleError(Dart_GetNativeArgument(arguments, 1));
-  int64_t size;
-  HandleError(Dart_IntegerToInt64(sizeHandle, &size));
-
-  Dart_Handle typeHandle = HandleError(Dart_GetNativeArgument(arguments, 2));
-  int64_t type;
-  HandleError(Dart_IntegerToInt64(typeHandle, &type));
-
-  Dart_Handle normalizedHandle =
-      HandleError(Dart_GetNativeArgument(arguments, 3));
-  bool normalized;
-  HandleError(Dart_BooleanValue(normalizedHandle, &normalized));
-
-  Dart_Handle strideHandle = HandleError(Dart_GetNativeArgument(arguments, 4));
-  int64_t stride;
-  HandleError(Dart_IntegerToInt64(strideHandle, &stride));
+  int64_t index = GetArgAsInt(arguments, 0);
+  int64_t size = GetArgAsInt(arguments, 1);
+  int64_t type = GetArgAsInt(arguments, 2);
+  bool normalized = GetArgAsBool(arguments, 3);
+  int64_t stride = GetArgAsInt(arguments, 4);
 
   Dart_Handle pointerHandle = HandleError(Dart_GetNativeArgument(arguments, 5));
   int64_t pointerValue;
   HandleError(Dart_IntegerToInt64(pointerHandle, &pointerValue));
   const void* pointer;
   pointer = const_cast<const void*>(reinterpret_cast<void*>(pointerValue));
 
   glVertexAttribPointer(index, size, type, normalized, stride, pointer);
   CheckGLError("glVertexAttribPointer");
   Dart_ExitScope();
 }
 
 void GLClearColor(Dart_NativeArguments arguments) {
   LOGI("GLClearColor");
   Dart_EnterScope();
-
-  Dart_Handle redHandle = HandleError(Dart_GetNativeArgument(arguments, 0));
-  double red;
-  HandleError(Dart_DoubleValue(redHandle, &red));
-
-  Dart_Handle greenHandle = HandleError(Dart_GetNativeArgument(arguments, 1));
-  double green;
-  HandleError(Dart_DoubleValue(greenHandle, &green));
-
-  Dart_Handle blueHandle = HandleError(Dart_GetNativeArgument(arguments, 2));
-  double blue;
-  HandleError(Dart_DoubleValue(blueHandle, &blue));
-
-  Dart_Handle alphaHandle = HandleError(Dart_GetNativeArgument(arguments, 3));
-  double alpha;
-  HandleError(Dart_DoubleValue(alphaHandle, &alpha));
-
+  double red = GetArgAsDouble(arguments, 0);
+  double green = GetArgAsDouble(arguments, 1);
+  double blue = GetArgAsDouble(arguments, 2);
+  double alpha = GetArgAsDouble(arguments, 3);
   glClearColor(red, green, blue, alpha);
   CheckGLError("glClearColor");
   Dart_ExitScope();
 }
 
 void GLClearDepth(Dart_NativeArguments arguments) {
   LOGI("GLClearDepth");
   Dart_EnterScope();
-
-  Dart_Handle depthHandle = HandleError(Dart_GetNativeArgument(arguments, 0));
-  double depth;
-  HandleError(Dart_DoubleValue(depthHandle, &depth));
-
+  double depth = GetArgAsDouble(arguments, 0);
   glClearDepthf(depth);
   CheckGLError("glClearDepthf");
   Dart_ExitScope();
 }
 
 void GLClear(Dart_NativeArguments arguments) {
   LOGI("GLClear");
   Dart_EnterScope();
   Dart_Handle maskHandle = HandleError(Dart_GetNativeArgument(arguments, 0));
   int64_t mask;
   HandleError(Dart_IntegerToInt64(maskHandle, &mask));
   glClear(mask);
   CheckGLError("glClear");
   Dart_ExitScope();
 }
 
+void ReturnGLIntConstant(Dart_NativeArguments arguments, int c) {
+  Dart_EnterScope();
+  SetIntReturnValue(arguments, c);
+  Dart_ExitScope();
+}
+
 void GLArrayBuffer(Dart_NativeArguments arguments) {
-  LOGI("GLArrayBuffer");
-  Dart_EnterScope();
-  Dart_Handle result = HandleError(Dart_NewInteger(GL_ARRAY_BUFFER));
-  Dart_SetReturnValue(arguments, result);
-  Dart_ExitScope();
+  ReturnGLIntConstant(arguments, GL_ARRAY_BUFFER);
 }
 
 void GLColorBufferBit(Dart_NativeArguments arguments) {
-  LOGI("GLColorBuffer");
-  Dart_EnterScope();
-  Dart_Handle result = HandleError(Dart_NewInteger(GL_COLOR_BUFFER_BIT));
-  Dart_SetReturnValue(arguments, result);
-  Dart_ExitScope();
+  ReturnGLIntConstant(arguments, GL_COLOR_BUFFER_BIT);
 }
 
 void GLCompileStatus(Dart_NativeArguments arguments) {
-  LOGI("GLCompileStatus");
-  Dart_EnterScope();
-  Dart_Handle result = HandleError(Dart_NewInteger(GL_COMPILE_STATUS));
-  Dart_SetReturnValue(arguments, result);
-  Dart_ExitScope();
+  ReturnGLIntConstant(arguments, GL_COMPILE_STATUS);
 }
 
 void GLDepthBufferBit(Dart_NativeArguments arguments) {
-  LOGI("GLDepthBufferBit");
-  Dart_EnterScope();
-  Dart_Handle result = HandleError(Dart_NewInteger(GL_DEPTH_BUFFER_BIT));
-  Dart_SetReturnValue(arguments, result);
-  Dart_ExitScope();
+  ReturnGLIntConstant(arguments, GL_DEPTH_BUFFER_BIT);
 }
 
 void GLFloat(Dart_NativeArguments arguments) {
-  Dart_EnterScope();
-  Dart_Handle result = HandleError(Dart_NewInteger(GL_FLOAT));
-  Dart_SetReturnValue(arguments, result);
-  Dart_ExitScope();
+  ReturnGLIntConstant(arguments, GL_FLOAT);
 }
 
 void GLFragmentShader(Dart_NativeArguments arguments) {
-  Dart_EnterScope();
-  Dart_Handle result = HandleError(Dart_NewInteger(GL_FRAGMENT_SHADER));
-  Dart_SetReturnValue(arguments, result);
-  Dart_ExitScope();
+  ReturnGLIntConstant(arguments, GL_FRAGMENT_SHADER);
 }
 
 void GLLinkStatus(Dart_NativeArguments arguments) {
-  Dart_EnterScope();
-  Dart_Handle result = HandleError(Dart_NewInteger(GL_LINK_STATUS));
-  Dart_SetReturnValue(arguments, result);
-  Dart_ExitScope();
+  ReturnGLIntConstant(arguments, GL_LINK_STATUS);
 }
 
 void GLStaticDraw(Dart_NativeArguments arguments) {
-  Dart_EnterScope();
-  Dart_Handle result = HandleError(Dart_NewInteger(GL_STATIC_DRAW));
-  Dart_SetReturnValue(arguments, result);
-  Dart_ExitScope();
+  ReturnGLIntConstant(arguments, GL_STATIC_DRAW);
 }
 
 void GLTriangleStrip(Dart_NativeArguments arguments) {
-  Dart_EnterScope();
-  Dart_Handle result = HandleError(Dart_NewInteger(GL_TRIANGLE_STRIP));
-  Dart_SetReturnValue(arguments, result);
-  Dart_ExitScope();
+  ReturnGLIntConstant(arguments, GL_TRIANGLE_STRIP);
 }
 
 void GLTriangles(Dart_NativeArguments arguments) {
-  Dart_EnterScope();
-  Dart_Handle result = HandleError(Dart_NewInteger(GL_TRIANGLES));
-  Dart_SetReturnValue(arguments, result);
-  Dart_ExitScope();
+  ReturnGLIntConstant(arguments, GL_TRIANGLES);
 }
 
 void GLTrue(Dart_NativeArguments arguments) {
-  Dart_EnterScope();
-  Dart_Handle result = HandleError(Dart_NewInteger(GL_TRUE));
-  Dart_SetReturnValue(arguments, result);
-  Dart_ExitScope();
+  ReturnGLIntConstant(arguments, GL_TRUE);
 }
 
 void GLVertexShader(Dart_NativeArguments arguments) {
-  Dart_EnterScope();
-  Dart_Handle result = HandleError(Dart_NewInteger(GL_VERTEX_SHADER));
-  Dart_SetReturnValue(arguments, result);
-  Dart_ExitScope();
+  ReturnGLIntConstant(arguments, GL_VERTEX_SHADER);
 }
 
 uint8_t* RandomArray(int seed, int length) {
   if (length <= 0 || length > 10000000) return NULL;
   uint8_t* values = reinterpret_cast<uint8_t*>(malloc(length));
   if (NULL == values) return NULL;
   srand(seed);
   for (int i = 0; i < length; ++i) {
     values[i] = rand() % 256;
   }
@@ skipping 41 matching lines @@
   if (service_port != ((Dart_Port)0)) {
     Dart_Handle send_port = HandleError(Dart_NewSendPort(service_port));
     Dart_SetReturnValue(arguments, send_port);
   }
   Dart_ExitScope();
 }
 
 void PlayBackground(Dart_NativeArguments arguments) {
   LOGI("PlayBackground");
   Dart_EnterScope();
-  const char* what = GetStringArg(arguments, 0);
-  PlayBackground(what);
+  const char* what = GetArgAsString(arguments, 0);
+  int rtn = PlayBackgroundSound(what);
+  SetIntReturnValue(arguments, rtn);
   Dart_ExitScope();
 }
 
 void StopBackground(Dart_NativeArguments arguments) {
   LOGI("StopBackground");
   Dart_EnterScope();
-  StopBackground();
+  StopBackgroundSound();
+  Dart_ExitScope();
+}
+
+void LoadSample(Dart_NativeArguments arguments) {
+  LOGI("LoadSample");
+  Dart_EnterScope();
+  const char* what = GetArgAsString(arguments, 0);
+  int rtn = LoadSoundSample(what);
+  SetIntReturnValue(arguments, rtn);
+  Dart_ExitScope();
+}
+
+void PlaySample(Dart_NativeArguments arguments) {
+  LOGI("PlaySample");
+  Dart_EnterScope();
+  const char* what = GetArgAsString(arguments, 0);
+  int rtn = PlaySoundSample(what);
+  SetIntReturnValue(arguments, rtn);
   Dart_ExitScope();
 }
 
 struct FunctionLookup {
   const char* name;
   Dart_NativeFunction function;
 };
 
 FunctionLookup function_list[] = {
     {"Log", Log},
+    {"LogError", LogError},
     {"SystemRand", SystemRand},
     {"SystemSrand", SystemSrand},
     {"EGLSwapBuffers", EGLSwapBuffers},
     {"GLAttachShader", GLAttachShader},
     {"GLBindBuffer", GLBindBuffer},
     {"GLBufferData", GLBufferData},
     {"GLClear", GLClear},
     {"GLClearColor", GLClearColor},
     {"GLClearDepth", GLClearDepth},
     {"GLCompileShader", GLCompileShader},
@@ skipping 40 matching lines @@
     {"GLTrue", GLTrue},
     {"GLStaticDraw", GLStaticDraw},
     {"GLVertexShader", GLVertexShader},
     {"GLGetShaderInfoLog", GLGetShaderInfoLog},
     {"GLGetProgramInfoLog", GLGetProgramInfoLog},
     {"RandomArray_ServicePort", RandomArrayServicePort},
 
     // Audio support.
     {"PlayBackground", PlayBackground},
     {"StopBackground", StopBackground},
+    {"LoadSample", LoadSample},
+    {"PlaySample", PlaySample},
 
     {NULL, NULL}};
 
 Dart_NativeFunction ResolveName(Dart_Handle name, int argc) {
   if (!Dart_IsString(name)) return NULL;
   Dart_NativeFunction result = NULL;
   Dart_EnterScope();
   const char* cname;
   HandleError(Dart_StringToCString(name, &cname));
   for (int i = 0; function_list[i].name != NULL; ++i) {
     if (strcmp(function_list[i].name, cname) == 0) {
       result = function_list[i].function;
       break;
     }
   }
   Dart_ExitScope();
   return result;
 }