command_buffer: Implement path rendering functions for CHROMIUM_path_rendering

Add support for path rendering functions with CHROMIUM_path_rendering in
gpu command buffer. CHROMIUM_path_rendering pseudo extension will use
NV_path_rendering (NVPR).

After this patch, CHROMIUM_path_rendering is able to draw solid color
paths.

Adds following functions to the command buffer:
glGenPathsCHROMIUM
glDeletePathsCHROMIUM
glIsPathCHROMIUM
glPathCommandsCHROMIUM
glPathParameterfCHROMIUM
glPathParameteriCHROMIUM
glPathStencilFuncCHROMIUM
glStencilFillPathCHROMIUM
glStencilStrokePathCHROMIUM
glCoverFillPathCHROMIUM
glCoverStrokePathCHROMIUM
glStencilThenCoverFillPathCHROMIUM
glStencilThenCoverStrokePathCHROMIUM

Noteworthy items:

NVPR has calls with multiple data arrays. These will be passed by
memcpy:ing the arrays into the same transfer buffer. The arrays
containing GLfloats are copied first, because floats have more strict
alignment needs than whatever is in the other array.

The functions exposed by the command buffer take in subset of the values
that plain NVPR functions accept. Also some functions do not take
exact same amount of parameters, rather only those parameters that
are expected to vary based on Skia implementation.

The change does not add vertexshader-less shader program support to the
command buffer. The caller is expected to use a dummy vertex
shader. NVPR calls will ignore the vertex shader.

Adds gpu::gles2::PathManager class that should be similar to other
resource manager classes. The intention is that paths can be shared in
similar manner as other resources.

Changes generator to generate feature_info check for Is -type of
functions.

Moves the path matrix related constants from glchromium.h to
gl2extchromium.h, the constants are not "normal" GLES constants, rather
they are part of the extension.

Skia will not yet use the extension, because texturing support and
instanced variants of the draw functions are not exposed by
CHROMIUM_path_rendering.

The extension will be available through flag --enable-gl-path-rendering
BUG=344330

Review URL: https://codereview.chromium.org/169403005

Cr-Commit-Position: refs/heads/master@{#338666}

1 files changed, 522 insertions, 10 deletions

diff --git a/gpu/command_buffer/tests/gl_chromium_path_rendering_unittest.cc b/gpu/command_buffer/tests/gl_chromium_path_rendering_unittest.cc
index 0d17b7c..57f5dd0 100644
--- a/gpu/command_buffer/tests/gl_chromium_path_rendering_unittest.cc
+++ b/gpu/command_buffer/tests/gl_chromium_path_rendering_unittest.cc
@@ -7,11 +7,15 @@
 #include <GLES2/gl2extchromium.h>
 #include <cmath>
 
+#include "base/command_line.h"
+#include "gpu/command_buffer/service/gpu_switches.h"
 #include "gpu/command_buffer/tests/gl_manager.h"
 #include "gpu/command_buffer/tests/gl_test_utils.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
+#define SHADER(Src) #Src
+
 namespace gpu {
 
 class CHROMIUMPathRenderingTest : public testing::Test {
@@ -22,7 +26,9 @@ class CHROMIUMPathRenderingTest : public testing::Test {
   void SetUp() override {
     GLManager::Options options;
     options.size = gfx::Size(kResolution, kResolution);
-    gl_.Initialize(options);
+    base::CommandLine command_line(*base::CommandLine::ForCurrentProcess());
+    command_line.AppendSwitch(switches::kEnableGLPathRendering);
+    gl_.InitializeWithCommandLine(options, &command_line);
   }
 
   void TearDown() override { gl_.Destroy(); }
@@ -37,13 +43,156 @@ class CHROMIUMPathRenderingTest : public testing::Test {
       EXPECT_EQ(static_cast<GLint>(round(expected[i])), actual[i]);
     }
   }
+
+  void SetupStateForTestPattern() {
+    glViewport(0, 0, kResolution, kResolution);
+    glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
+    glStencilMask(0xffffffff);
+    glClearStencil(0);
+    glClear(GL_COLOR_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
+
+    static const char* kVertexShaderSource =
+        SHADER(void main() { gl_Position = vec4(1); });
+    static const char* kFragmentShaderSource =
+        SHADER(precision mediump float; uniform vec4 color;
+               void main() { gl_FragColor = color; });
+
+    GLuint program =
+        GLTestHelper::LoadProgram(kVertexShaderSource, kFragmentShaderSource);
+    glUseProgram(program);
+    color_loc_ = glGetUniformLocation(program, "color");
+    glDeleteProgram(program);
+
+    // Set up orthogonal projection with near/far plane distance of 2.
+    static GLfloat matrix[16] = {2.0f / (kResolution - 1),
+                                 0.0f,
+                                 0.0f,
+                                 0.0f,
+                                 0.0f,
+                                 2.0f / (kResolution - 1),
+                                 0.0f,
+                                 0.0f,
+                                 0.0f,
+                                 0.0f,
+                                 -1.0f,
+                                 0.0f,
+                                 -1.0f,
+                                 -1.0f,
+                                 0.0f,
+                                 1.0f};
+    glMatrixLoadfCHROMIUM(GL_PATH_PROJECTION_CHROMIUM, matrix);
+    glMatrixLoadIdentityCHROMIUM(GL_PATH_MODELVIEW_CHROMIUM);
+
+    glEnable(GL_STENCIL_TEST);
+
+    GLTestHelper::CheckGLError("no errors at state setup", __LINE__);
+  }
+
+  void SetupPathStateForTestPattern(GLuint path) {
+    static const GLubyte kCommands[] = {GL_MOVE_TO_CHROMIUM,
+                                        GL_LINE_TO_CHROMIUM,
+                                        GL_QUADRATIC_CURVE_TO_CHROMIUM,
+                                        GL_CUBIC_CURVE_TO_CHROMIUM,
+                                        GL_CLOSE_PATH_CHROMIUM};
+
+    static const GLfloat kCoords[] = {50.0f,
+                                      50.0f,
+                                      75.0f,
+                                      75.0f,
+                                      100.0f,
+                                      62.5f,
+                                      50.0f,
+                                      25.5f,
+                                      0.0f,
+                                      62.5f,
+                                      50.0f,
+                                      50.0f,
+                                      25.0f,
+                                      75.0f};
+
+    glPathCommandsCHROMIUM(path, arraysize(kCommands), kCommands,
+                           arraysize(kCoords), GL_FLOAT, kCoords);
+
+    glPathParameterfCHROMIUM(path, GL_PATH_STROKE_WIDTH_CHROMIUM, 5.0f);
+    glPathParameterfCHROMIUM(path, GL_PATH_MITER_LIMIT_CHROMIUM, 1.0f);
+    glPathParameterfCHROMIUM(path, GL_PATH_STROKE_BOUND_CHROMIUM, .02f);
+    glPathParameteriCHROMIUM(path, GL_PATH_JOIN_STYLE_CHROMIUM,
+                             GL_ROUND_CHROMIUM);
+    glPathParameteriCHROMIUM(path, GL_PATH_END_CAPS_CHROMIUM,
+                             GL_SQUARE_CHROMIUM);
+  }
+
+  void VerifyTestPatternFill(float x, float y) {
+    static const float kFillCoords[] = {
+        55.0f, 55.0f, 50.0f, 28.0f, 66.0f, 63.0f};
+    static const uint8 kBlue[] = {0, 0, 255, 255};
+
+    for (size_t i = 0; i < arraysize(kFillCoords); i += 2) {
+      float fx = kFillCoords[i];
+      float fy = kFillCoords[i + 1];
+
+      EXPECT_TRUE(GLTestHelper::CheckPixels(x + fx, y + fy, 1, 1, 0, kBlue));
+    }
+  }
+
+  void VerifyTestPatternBg(float x, float y) {
+    const float kBackgroundCoords[] = {80.0f, 80.0f, 20.0f, 20.0f, 90.0f, 1.0f};
+    const uint8 kExpectedColor[] = {0, 0, 0, 0};
+
+    for (size_t i = 0; i < arraysize(kBackgroundCoords); i += 2) {
+      float bx = kBackgroundCoords[i];
+      float by = kBackgroundCoords[i + 1];
+
+      EXPECT_TRUE(
+          GLTestHelper::CheckPixels(x + bx, y + by, 1, 1, 0, kExpectedColor));
+    }
+  }
+
+  void VerifyTestPatternStroke(float x, float y) {
+    // Inside the stroke we should have green.
+    const uint8 kGreen[] = {0, 255, 0, 255};
+    EXPECT_TRUE(GLTestHelper::CheckPixels(x + 50, y + 53, 1, 1, 0, kGreen));
+    EXPECT_TRUE(GLTestHelper::CheckPixels(x + 26, y + 76, 1, 1, 0, kGreen));
+
+    // Outside the path we should have black.
+    const uint8 black[] = {0, 0, 0, 0};
+    EXPECT_TRUE(GLTestHelper::CheckPixels(x + 10, y + 10, 1, 1, 0, black));
+    EXPECT_TRUE(GLTestHelper::CheckPixels(x + 80, y + 80, 1, 1, 0, black));
+  }
+
+  void TryAllDrawFunctions(GLuint path, GLenum expected_error) {
+    glStencilFillPathCHROMIUM(path, GL_COUNT_UP_CHROMIUM, 0x7F);
+    EXPECT_EQ(expected_error, glGetError());
+
+    glStencilFillPathCHROMIUM(path, GL_COUNT_UP_CHROMIUM, 0x7F);
+    EXPECT_EQ(expected_error, glGetError());
+
+    glStencilStrokePathCHROMIUM(path, 0x80, 0x80);
+    EXPECT_EQ(expected_error, glGetError());
+
+    glCoverFillPathCHROMIUM(path, GL_BOUNDING_BOX_CHROMIUM);
+    EXPECT_EQ(expected_error, glGetError());
+
+    glCoverStrokePathCHROMIUM(path, GL_BOUNDING_BOX_CHROMIUM);
+    EXPECT_EQ(expected_error, glGetError());
+
+    glStencilThenCoverStrokePathCHROMIUM(path, 0x80, 0x80,
+                                         GL_BOUNDING_BOX_CHROMIUM);
+    EXPECT_EQ(expected_error, glGetError());
+
+    glStencilThenCoverFillPathCHROMIUM(path, GL_COUNT_UP_CHROMIUM, 0x7F,
+                                       GL_BOUNDING_BOX_CHROMIUM);
+    EXPECT_EQ(expected_error, glGetError());
+  }
+
   GLManager gl_;
+  GLint color_loc_;
 };
 
 TEST_F(CHROMIUMPathRenderingTest, TestMatrix) {
-  if (!GLTestHelper::HasExtension("GL_CHROMIUM_path_rendering")) {
+  if (!GLTestHelper::HasExtension("GL_CHROMIUM_path_rendering"))
     return;
-  }
+
   static const GLfloat kIdentityMatrix[16] = {
       1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f,
       0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f};
@@ -86,25 +235,388 @@ TEST_F(CHROMIUMPathRenderingTest, TestMatrix) {
 }
 
 TEST_F(CHROMIUMPathRenderingTest, TestMatrixErrors) {
-  if (!GLTestHelper::HasExtension("GL_CHROMIUM_path_rendering")) {
+  if (!GLTestHelper::HasExtension("GL_CHROMIUM_path_rendering"))
     return;
-  }
+
   GLfloat mf[16];
   memset(mf, 0, sizeof(mf));
 
-  // This should fail.
+  glMatrixLoadfCHROMIUM(GL_PATH_MODELVIEW_CHROMIUM, mf);
+  EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
+
+  glMatrixLoadIdentityCHROMIUM(GL_PATH_PROJECTION_CHROMIUM);
+  EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
+
+  // Test that invalid matrix targets fail.
   glMatrixLoadfCHROMIUM(GL_PATH_MODELVIEW_CHROMIUM - 1, mf);
   EXPECT_EQ(static_cast<GLenum>(GL_INVALID_ENUM), glGetError());
 
-  glMatrixLoadfCHROMIUM(GL_PATH_MODELVIEW_CHROMIUM, mf);
+  // Test that invalid matrix targets fail.
+  glMatrixLoadIdentityCHROMIUM(GL_PATH_PROJECTION_CHROMIUM + 1);
+  EXPECT_EQ(static_cast<GLenum>(GL_INVALID_ENUM), glGetError());
+}
+
+TEST_F(CHROMIUMPathRenderingTest, TestSimpleCalls) {
+  if (!GLTestHelper::HasExtension("GL_CHROMIUM_path_rendering"))
+    return;
+
+  // This is unspecified in NV_path_rendering.
+  EXPECT_EQ(0u, glGenPathsCHROMIUM(0));
+
+  GLuint path = glGenPathsCHROMIUM(1);
+  EXPECT_NE(path, 0u);
+  glDeletePathsCHROMIUM(path, 1);
   EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
 
-  // This should fail.
-  glMatrixLoadIdentityCHROMIUM(GL_PATH_PROJECTION_CHROMIUM + 1);
+  GLuint first_path = glGenPathsCHROMIUM(5);
+  EXPECT_NE(first_path, 0u);
+  glDeletePathsCHROMIUM(first_path, 5);
+  EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
+
+  // Test deleting paths that are not actually allocated:
+  // "unused names in /paths/ are silently ignored".
+  first_path = glGenPathsCHROMIUM(5);
+  EXPECT_NE(first_path, 0u);
+  glDeletePathsCHROMIUM(first_path, 6);
+  EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
+
+  GLsizei big_range = 0xffff;
+  // Setting big_range = std::numeric_limits<GLsizei>::max() should go through
+  // too, as far as NV_path_rendering is concerned. Current chromium side id
+  // allocator will use too much memory.
+  first_path = glGenPathsCHROMIUM(big_range);
+  EXPECT_NE(first_path, 0u);
+  glDeletePathsCHROMIUM(first_path, big_range);
+  EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
+
+  // Test glIsPathCHROMIUM().
+  path = glGenPathsCHROMIUM(1);
+  EXPECT_FALSE(glIsPathCHROMIUM(path));
+  GLubyte commands[] = {GL_MOVE_TO_CHROMIUM, GL_CLOSE_PATH_CHROMIUM};
+  GLfloat coords[] = {50.0f, 50.0f};
+  glPathCommandsCHROMIUM(path, arraysize(commands), commands, arraysize(coords),
+                         GL_FLOAT, coords);
+  EXPECT_TRUE(glIsPathCHROMIUM(path));
+  glDeletePathsCHROMIUM(path, 1);
+  EXPECT_FALSE(glIsPathCHROMIUM(path));
+}
+
+TEST_F(CHROMIUMPathRenderingTest, TestGenDeleteErrors) {
+  if (!GLTestHelper::HasExtension("GL_CHROMIUM_path_rendering"))
+    return;
+
+  // GenPaths / DeletePaths tests.
+  // std::numeric_limits<GLuint>::max() is wrong for GLsizei.
+  GLuint first_path = glGenPathsCHROMIUM(std::numeric_limits<GLuint>::max());
+  EXPECT_EQ(first_path, 0u);
+  EXPECT_EQ(static_cast<GLenum>(GL_INVALID_VALUE), glGetError());
+
+  first_path = glGenPathsCHROMIUM(-1);
+  EXPECT_EQ(first_path, 0u);
+  EXPECT_EQ(static_cast<GLenum>(GL_INVALID_VALUE), glGetError());
+
+  glDeletePathsCHROMIUM(1, -5);
+  EXPECT_EQ(static_cast<GLenum>(GL_INVALID_VALUE), glGetError());
+
+  first_path = glGenPathsCHROMIUM(-1);
+  EXPECT_EQ(first_path, 0u);
+  EXPECT_EQ(static_cast<GLenum>(GL_INVALID_VALUE), glGetError());
+
+  // Test that delete with first_id and range such that first_id + range
+  // overflows the GLuint. Example:
+  // Range is 0x7fffffff. First id is X. Last id will be X + 0x7ffffffe.
+  // X = 0x80000001 would succeed, where as X = 0x80000002 would fail.
+  // To get 0x80000002, we need to allocate first 0x7fffffff and then
+  // 3 (0x80000000, 0x80000001 and 0x80000002).
+  // While not guaranteed by the API, we expect the implementation
+  // hands us deterministic ids.
+  first_path = glGenPathsCHROMIUM(std::numeric_limits<GLsizei>::max());
+  EXPECT_EQ(first_path, 1u);
+  EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
+
+  GLuint additional_paths = glGenPathsCHROMIUM(3);
+  EXPECT_EQ(additional_paths,
+            static_cast<GLuint>(std::numeric_limits<GLsizei>::max()) + 1u);
+  EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
+
+  // Test that passing a range so big that it would overflow client_id
+  // + range - 1 check causes an error.
+  glDeletePathsCHROMIUM(additional_paths + 2u,
+                        std::numeric_limits<GLsizei>::max());
+  EXPECT_EQ(static_cast<GLenum>(GL_INVALID_OPERATION), glGetError());
+
+  // Cleanup the above allocations. Also test that passing max value still
+  // works.
+  glDeletePathsCHROMIUM(1, std::numeric_limits<GLsizei>::max());
+  EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
+  glDeletePathsCHROMIUM(std::numeric_limits<GLsizei>::max(),
+                        std::numeric_limits<GLsizei>::max());
+  EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
+}
+
+TEST_F(CHROMIUMPathRenderingTest, TestPathParameterErrors) {
+  if (!GLTestHelper::HasExtension("GL_CHROMIUM_path_rendering"))
+    return;
+
+  GLuint path = glGenPathsCHROMIUM(1);
+  // PathParameter*: Wrong value for the pname should fail.
+  glPathParameteriCHROMIUM(path, GL_PATH_JOIN_STYLE_CHROMIUM, GL_FLAT_CHROMIUM);
+  EXPECT_EQ(static_cast<GLenum>(GL_INVALID_VALUE), glGetError());
+  glPathParameterfCHROMIUM(path, GL_PATH_END_CAPS_CHROMIUM,
+                           GL_MITER_REVERT_CHROMIUM);
+  EXPECT_EQ(static_cast<GLenum>(GL_INVALID_VALUE), glGetError());
+
+  // PathParameter*: Wrong floating-point value should fail.
+  glPathParameterfCHROMIUM(path, GL_PATH_STROKE_WIDTH_CHROMIUM, -0.1f);
+  EXPECT_EQ(static_cast<GLenum>(GL_INVALID_VALUE), glGetError());
+  glPathParameterfCHROMIUM(path, GL_PATH_MITER_LIMIT_CHROMIUM,
+                           std::numeric_limits<float>::quiet_NaN());
+  EXPECT_EQ(static_cast<GLenum>(GL_INVALID_VALUE), glGetError());
+  glPathParameterfCHROMIUM(path, GL_PATH_MITER_LIMIT_CHROMIUM,
+                           std::numeric_limits<float>::infinity());
+  EXPECT_EQ(static_cast<GLenum>(GL_INVALID_VALUE), glGetError());
+
+  // PathParameter*: Wrong pname should fail.
+  glPathParameteriCHROMIUM(path, GL_PATH_STROKE_WIDTH_CHROMIUM - 1, 5);
   EXPECT_EQ(static_cast<GLenum>(GL_INVALID_ENUM), glGetError());
+  glDeletePathsCHROMIUM(path, 1);
+}
 
-  glMatrixLoadIdentityCHROMIUM(GL_PATH_PROJECTION_CHROMIUM);
+TEST_F(CHROMIUMPathRenderingTest, TestPathObjectState) {
+  if (!GLTestHelper::HasExtension("GL_CHROMIUM_path_rendering"))
+    return;
+
+  glViewport(0, 0, kResolution, kResolution);
+  glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
+  glStencilMask(0xffffffff);
+  glClearStencil(0);
+  glClear(GL_COLOR_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
+  glPathStencilFuncCHROMIUM(GL_ALWAYS, 0, 0xFF);
+  glStencilOp(GL_KEEP, GL_KEEP, GL_ZERO);
+
+  // Test that trying to draw non-existing paths does not produce errors or
+  // results.
+  GLuint non_existing_paths[] = {0, 55, 74744};
+  for (auto& p : non_existing_paths) {
+    EXPECT_FALSE(glIsPathCHROMIUM(p));
+    EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
+    TryAllDrawFunctions(p, GL_NO_ERROR);
+  }
+
+  // Path name marked as used but without path object state causes
+  // a GL error upon any draw command.
+  GLuint path = glGenPathsCHROMIUM(1);
+  EXPECT_FALSE(glIsPathCHROMIUM(path));
+  TryAllDrawFunctions(path, GL_INVALID_OPERATION);
+  glDeletePathsCHROMIUM(path, 1);
+
+  // Document a bit of an inconsistency: path name marked as used but without
+  // path object state causes a GL error upon any draw command (tested above).
+  // Path name that had path object state, but then was "cleared", still has a
+  // path object state, even though the state is empty.
+  path = glGenPathsCHROMIUM(1);
+  EXPECT_FALSE(glIsPathCHROMIUM(path));
+  GLubyte commands[] = {GL_MOVE_TO_CHROMIUM, GL_CLOSE_PATH_CHROMIUM};
+  GLfloat coords[] = {50.0f, 50.0f};
+  glPathCommandsCHROMIUM(path, arraysize(commands), commands, arraysize(coords),
+                         GL_FLOAT, coords);
+  EXPECT_TRUE(glIsPathCHROMIUM(path));
+  glPathCommandsCHROMIUM(path, 0, NULL, 0, GL_FLOAT, NULL);
+  EXPECT_TRUE(glIsPathCHROMIUM(path));  // The surprise.
+  TryAllDrawFunctions(path, GL_NO_ERROR);
+  glDeletePathsCHROMIUM(path, 1);
+
+  // Document a bit of an inconsistency: "clearing" a used path name causes
+  // path to acquire state.
+  path = glGenPathsCHROMIUM(1);
+  EXPECT_FALSE(glIsPathCHROMIUM(path));
+  glPathCommandsCHROMIUM(path, 0, NULL, 0, GL_FLOAT, NULL);
+  EXPECT_TRUE(glIsPathCHROMIUM(path));  // The surprise.
+  glDeletePathsCHROMIUM(path, 1);
+
+  // Make sure nothing got drawn by the drawing commands that should not produce
+  // anything.
+  const uint8 black[] = {0, 0, 0, 0};
+  EXPECT_TRUE(
+      GLTestHelper::CheckPixels(0, 0, kResolution, kResolution, 0, black));
+}
+
+TEST_F(CHROMIUMPathRenderingTest, TestUnnamedPathsErrors) {
+  if (!GLTestHelper::HasExtension("GL_CHROMIUM_path_rendering"))
+    return;
+
+  // Unnamed paths: Trying to create a path object with non-existing path name
+  // produces error.  (Not a error in real NV_path_rendering).
+  EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
+  GLubyte commands[] = {GL_MOVE_TO_CHROMIUM, GL_CLOSE_PATH_CHROMIUM};
+  GLfloat coords[] = {50.0f, 50.0f};
+  glPathCommandsCHROMIUM(555, arraysize(commands), commands, arraysize(coords),
+                         GL_FLOAT, coords);
+  EXPECT_EQ(static_cast<GLenum>(GL_INVALID_OPERATION), glGetError());
+
+  // PathParameter*: Using non-existing path object produces error.
+  EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
+  glPathParameterfCHROMIUM(555, GL_PATH_STROKE_WIDTH_CHROMIUM, 5.0f);
+  EXPECT_EQ(static_cast<GLenum>(GL_INVALID_OPERATION), glGetError());
+
+  EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
+  glPathParameteriCHROMIUM(555, GL_PATH_JOIN_STYLE_CHROMIUM, GL_ROUND_CHROMIUM);
+  EXPECT_EQ(static_cast<GLenum>(GL_INVALID_OPERATION), glGetError());
+}
+
+TEST_F(CHROMIUMPathRenderingTest, TestPathCommandsErrors) {
+  if (!GLTestHelper::HasExtension("GL_CHROMIUM_path_rendering"))
+    return;
+
+  static const GLenum kInvalidCoordType = GL_NONE;
+
+  GLuint path = glGenPathsCHROMIUM(1);
+  GLubyte commands[] = {GL_MOVE_TO_CHROMIUM, GL_CLOSE_PATH_CHROMIUM};
+  GLfloat coords[] = {50.0f, 50.0f};
+
+  glPathCommandsCHROMIUM(path, arraysize(commands), commands, -4, GL_FLOAT,
+                         coords);
+  EXPECT_EQ(static_cast<GLenum>(GL_INVALID_VALUE), glGetError());
+
+  glPathCommandsCHROMIUM(path, -1, commands, arraysize(coords), GL_FLOAT,
+                         coords);
+  EXPECT_EQ(static_cast<GLenum>(GL_INVALID_VALUE), glGetError());
+
+  glPathCommandsCHROMIUM(path, arraysize(commands), commands, arraysize(coords),
+                         kInvalidCoordType, coords);
+  EXPECT_EQ(static_cast<GLenum>(GL_INVALID_ENUM), glGetError());
+
+  // These can not distinquish between the check that should fail them.
+  // This should fail due to coord count * float size overflow.
+  glPathCommandsCHROMIUM(path, arraysize(commands), commands,
+                         std::numeric_limits<GLsizei>::max(), GL_FLOAT, coords);
+  // This should fail due to cmd count + coord count * short size.
+  glPathCommandsCHROMIUM(path, arraysize(commands), commands,
+                         std::numeric_limits<GLsizei>::max(), GL_SHORT, coords);
+  EXPECT_EQ(static_cast<GLenum>(GL_INVALID_OPERATION), glGetError());
+
+  glDeletePathsCHROMIUM(path, 1);
+}
+
+TEST_F(CHROMIUMPathRenderingTest, TestPathRenderingInvalidArgs) {
+  if (!GLTestHelper::HasExtension("GL_CHROMIUM_path_rendering"))
+    return;
+
+  GLuint path = glGenPathsCHROMIUM(1);
+  glPathCommandsCHROMIUM(path, 0, NULL, 0, GL_FLOAT, NULL);
+
+  // Verify that normal calls work.
+  glStencilFillPathCHROMIUM(path, GL_COUNT_UP_CHROMIUM, 0x7F);
   EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
+  glStencilThenCoverFillPathCHROMIUM(path, GL_COUNT_UP_CHROMIUM, 0x7F,
+                                     GL_BOUNDING_BOX_CHROMIUM);
+  EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
+
+  // Using invalid fill mode causes INVALID_ENUM.
+  glStencilFillPathCHROMIUM(path, GL_COUNT_UP_CHROMIUM - 1, 0x7F);
+  EXPECT_EQ(static_cast<GLenum>(GL_INVALID_ENUM), glGetError());
+  glStencilThenCoverFillPathCHROMIUM(path, GL_COUNT_UP_CHROMIUM - 1, 0x7F,
+                                     GL_BOUNDING_BOX_CHROMIUM);
+  EXPECT_EQ(static_cast<GLenum>(GL_INVALID_ENUM), glGetError());
+
+  // Using invalid cover mode causes INVALID_ENUM.
+  glCoverFillPathCHROMIUM(path, GL_CONVEX_HULL_CHROMIUM - 1);
+  EXPECT_EQ(static_cast<GLenum>(GL_INVALID_ENUM), glGetError());
+  glStencilThenCoverFillPathCHROMIUM(path, GL_COUNT_UP_CHROMIUM, 0x7F,
+                                     GL_BOUNDING_BOX_CHROMIUM + 1);
+  EXPECT_EQ(static_cast<GLenum>(GL_INVALID_ENUM), glGetError());
+
+  // Using mask+1 not being power of two causes INVALID_VALUE with up/down fill
+  // mode.
+  glStencilFillPathCHROMIUM(path, GL_COUNT_UP_CHROMIUM, 0x40);
+  EXPECT_EQ(static_cast<GLenum>(GL_INVALID_VALUE), glGetError());
+  glStencilThenCoverFillPathCHROMIUM(path, GL_COUNT_DOWN_CHROMIUM, 12,
+                                     GL_BOUNDING_BOX_CHROMIUM);
+  EXPECT_EQ(static_cast<GLenum>(GL_INVALID_VALUE), glGetError());
+
+  glDeletePathsCHROMIUM(path, 1);
+}
+
+// Tests that drawing with CHROMIUM_path_rendering functions work.
+TEST_F(CHROMIUMPathRenderingTest, TestPathRendering) {
+  if (!GLTestHelper::HasExtension("GL_CHROMIUM_path_rendering"))
+    return;
+
+  static const float kBlue[] = {0.0f, 0.0f, 1.0f, 1.0f};
+  static const float kGreen[] = {0.0f, 1.0f, 0.0f, 1.0f};
+
+  SetupStateForTestPattern();
+
+  GLuint path = glGenPathsCHROMIUM(1);
+  SetupPathStateForTestPattern(path);
+
+  // Do the stencil fill, cover fill, stencil stroke, cover stroke
+  // in unconventional order:
+  // 1) stencil the stroke in stencil high bit
+  // 2) stencil the fill in low bits
+  // 3) cover the fill
+  // 4) cover the stroke
+  // This is done to check that glPathStencilFunc works, eg the mask
+  // goes through. Stencil func is not tested ATM, for simplicity.
+
+  glPathStencilFuncCHROMIUM(GL_ALWAYS, 0, 0xFF);
+  glStencilStrokePathCHROMIUM(path, 0x80, 0x80);
+
+  glPathStencilFuncCHROMIUM(GL_ALWAYS, 0, 0x7F);
+  glStencilFillPathCHROMIUM(path, GL_COUNT_UP_CHROMIUM, 0x7F);
+
+  glStencilFunc(GL_LESS, 0, 0x7F);
+  glStencilOp(GL_KEEP, GL_KEEP, GL_ZERO);
+  glUniform4fv(color_loc_, 1, kBlue);
+  glCoverFillPathCHROMIUM(path, GL_BOUNDING_BOX_CHROMIUM);
+
+  glStencilFunc(GL_EQUAL, 0x80, 0x80);
+  glStencilOp(GL_KEEP, GL_KEEP, GL_ZERO);
+  glUniform4fv(color_loc_, 1, kGreen);
+  glCoverStrokePathCHROMIUM(path, GL_CONVEX_HULL_CHROMIUM);
+
+  glDeletePathsCHROMIUM(path, 1);
+
+  // Verify the image.
+  VerifyTestPatternFill(0.0f, 0.0f);
+  VerifyTestPatternBg(0.0f, 0.0f);
+  VerifyTestPatternStroke(0.0f, 0.0f);
+}
+
+// Tests that drawing with CHROMIUM_path_rendering
+// StencilThenCover{Stroke,Fill}Path functions work.
+TEST_F(CHROMIUMPathRenderingTest, TestPathRenderingThenFunctions) {
+  if (!GLTestHelper::HasExtension("GL_CHROMIUM_path_rendering"))
+    return;
+
+  static float kBlue[] = {0.0f, 0.0f, 1.0f, 1.0f};
+  static float kGreen[] = {0.0f, 1.0f, 0.0f, 1.0f};
+
+  SetupStateForTestPattern();
+
+  GLuint path = glGenPathsCHROMIUM(1);
+  SetupPathStateForTestPattern(path);
+
+  glPathStencilFuncCHROMIUM(GL_ALWAYS, 0, 0xFF);
+  glStencilFunc(GL_EQUAL, 0x80, 0x80);
+  glStencilOp(GL_KEEP, GL_KEEP, GL_ZERO);
+  glUniform4fv(color_loc_, 1, kGreen);
+  glStencilThenCoverStrokePathCHROMIUM(path, 0x80, 0x80,
+                                       GL_BOUNDING_BOX_CHROMIUM);
+
+  glPathStencilFuncCHROMIUM(GL_ALWAYS, 0, 0x7F);
+  glStencilFunc(GL_LESS, 0, 0x7F);
+  glStencilOp(GL_KEEP, GL_KEEP, GL_ZERO);
+  glUniform4fv(color_loc_, 1, kBlue);
+  glStencilThenCoverFillPathCHROMIUM(path, GL_COUNT_UP_CHROMIUM, 0x7F,
+                                     GL_CONVEX_HULL_CHROMIUM);
+
+  glDeletePathsCHROMIUM(path, 1);
+
+  // Verify the image.
+  VerifyTestPatternFill(0.0f, 0.0f);
+  VerifyTestPatternBg(0.0f, 0.0f);
+  VerifyTestPatternStroke(0.0f, 0.0f);
 }
 
 }  // namespace gpu