graphics_WindowManagerGraphicsCapture test taking screenshots and comparing them to reference images.

BUG=2054
TEST=graphics_WindowManagerGraphicsCapture

Review URL: http://codereview.chromium.org/1972001
diff --git a/client/deps/glbench/src/main.h b/client/deps/glbench/src/main.h
index d103f1e..f9aa791 100644
--- a/client/deps/glbench/src/main.h
+++ b/client/deps/glbench/src/main.h
@@ -36,6 +36,7 @@
     F(glShaderSource, PFNGLSHADERSOURCEPROC) \
     F(glUniform1f, PFNGLUNIFORM1FPROC) \
     F(glUniform1i, PFNGLUNIFORM1IPROC) \
+    F(glUniform4fv, PFNGLUNIFORM4FVPROC) \
     F(glUseProgram, PFNGLUSEPROGRAMPROC) \
     F(glVertexAttribPointer, PFNGLVERTEXATTRIBPOINTERPROC) \
     F(glXSwapIntervalSGI, PFNGLXSWAPINTERVALSGIPROC) \
diff --git a/client/deps/glbench/src/windowmanagertest.cc b/client/deps/glbench/src/windowmanagertest.cc
index 934fb10..2fb4541 100644
--- a/client/deps/glbench/src/windowmanagertest.cc
+++ b/client/deps/glbench/src/windowmanagertest.cc
@@ -51,26 +51,31 @@
 
 
 const char kVertexShader[] =
-    "attribute vec4 c;"
+    "attribute vec4 vertices;"
     "void main() {"
-    "    gl_Position = c;"
-    "    gl_TexCoord[0] = vec4(c.y, c.x, 0.0, 0.0);"
+    "    gl_Position = vertices;"
+    "    gl_TexCoord[0] = vec4(vertices.y, vertices.x, 0.0, 0.0);"
     "}";
 
 const char kFragmentShader[] =
     "uniform sampler2D tex;"
+    "uniform vec4 color;"
     "void main() {"
-    "    gl_FragColor = texture2D(tex, gl_TexCoord[0].xy);"
+    "    gl_FragColor = color * texture2D(tex, gl_TexCoord[0].xy);"
     "}";
 
-
-// If refresh is set to zero, we enable vsync.  Otherwise we redraw that many
-// times a second.
-DEFINE_int32(seconds_to_run, 10, "seconds to run application for");
+// Command line flags
+DEFINE_double(screenshot1_sec, 2.f, "seconds delay before screenshot1_cmd");
+DEFINE_double(screenshot2_sec, 1.f, "seconds delay before screenshot2_cmd");
+DEFINE_string(screenshot1_cmd, "", "system command to take a screen shot 1");
+DEFINE_string(screenshot2_cmd, "", "system command to take a screen shot 2");
+DEFINE_double(cooldown_sec, 1.f, "seconds delay after all screenshots");
 
 int main(int argc, char* argv[]) {
+  // Configure full screen
   g_width = -1;
   g_height = -1;
+
   google::ParseCommandLineFlags(&argc, &argv, true);
 
   if (!Init()) {
@@ -94,19 +99,64 @@
   };
 
   GLuint program = InitShaderProgram(kVertexShader, kFragmentShader);
-  int attribute_index = glGetAttribLocation(program, "c");
+  int attribute_index = glGetAttribLocation(program, "vertices");
   glVertexAttribPointer(attribute_index, 2, GL_FLOAT, GL_FALSE, 0, vertices);
   glEnableVertexAttribArray(attribute_index);
 
   int texture_sampler = glGetUniformLocation(program, "tex");
-  glUniform1f(texture_sampler, 0);
+  glUniform1i(texture_sampler, 0);
 
-  uint64_t wait_until_done = GetUTime() + 1000000ULL * FLAGS_seconds_to_run;
+  int display_color = glGetUniformLocation(program, "color");
+  float white[4] = {1.0f, 1.0f, 1.0f, 1.0f};
+  float blue[4] = {0.5f, 0.5f, 1.0f, 1.0f};
+
+  uint64_t last_event_time = GetUTime();
+  enum State {
+    kStateScreenShot1,
+    kStateScreenShot2,
+    kStateCooldown,
+    kStateExit
+  } state = kStateScreenShot1;
+  float seconds_delay_for_next_state[] = {
+      FLAGS_screenshot1_sec,
+      FLAGS_screenshot2_sec,
+      FLAGS_cooldown_sec,
+      0
+  };
+
   do {
+    // Draw
     glClear(GL_COLOR_BUFFER_BIT);
+    if (state == kStateScreenShot1)
+      glUniform4fv(display_color, 1, white);
+    else
+      glUniform4fv(display_color, 1, blue);
     glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
     SwapBuffers();
-  } while (GetUTime() < wait_until_done);
+
+    // Loop until next event
+    float seconds_since_last_event =
+        static_cast<float>(GetUTime() - last_event_time) / 1000000ULL;
+    if (seconds_since_last_event < seconds_delay_for_next_state[state])
+      continue;
+
+    // State change. Perform action.
+    switch(state) {
+      case kStateScreenShot1:
+        system(FLAGS_screenshot1_cmd.c_str());
+        break;
+      case kStateScreenShot2:
+        system(FLAGS_screenshot2_cmd.c_str());
+        break;
+      default:
+        break;
+    }
+
+    // Advance to next state
+    last_event_time = GetUTime();
+    state = static_cast<State>(state + 1);
+
+  } while (state != kStateExit);
 
   glDeleteTextures(1, &texture);
   DestroyContext();
diff --git a/client/site_tests/graphics_WindowManagerGraphicsCapture/graphics_WindowManagerGraphicsCapture.py b/client/site_tests/graphics_WindowManagerGraphicsCapture/graphics_WindowManagerGraphicsCapture.py
index 77c9ce6..b87a7dc 100644
--- a/client/site_tests/graphics_WindowManagerGraphicsCapture/graphics_WindowManagerGraphicsCapture.py
+++ b/client/site_tests/graphics_WindowManagerGraphicsCapture/graphics_WindowManagerGraphicsCapture.py
@@ -18,14 +18,42 @@
         dep = 'glbench'
         dep_dir = os.path.join(self.autodir, 'deps', dep)
         self.job.install_pkg(dep, 'dep', dep_dir)
-  
+    
+        screenshot1_reference = os.path.join(self.bindir,
+                                            "screenshot1_reference")
+        screenshot1_generated = os.path.join(self.resultsdir,
+                                            "screenshot1_generated")
+        screenshot1_resized = os.path.join(self.resultsdir,
+                                            "screenshot1_generated_resized")
+        screenshot2_reference = os.path.join(self.bindir,
+                                            "screenshot2_reference")
+        screenshot2_generated = os.path.join(self.resultsdir,
+                                            "screenshot2_generated")
+        screenshot2_resized = os.path.join(self.resultsdir,
+                                            "screenshot2_generated_resized")
+
         exefile = os.path.join(self.autodir, 'deps/glbench/windowmanagertest')
-        
         # Enable running in window manager
         exefile = ('chvt 1 && DISPLAY=:0 XAUTHORITY=/home/chronos/.Xauthority ' 
                    + exefile)
 
-        options = "--seconds_to_run 10"
-        cmd = "%s %s" % (exefile, options)
-        logging.info("command launched: %s" % cmd)
-        self.results = utils.system_output(cmd, retain_output=True)
+        # Delay before screenshot: 1 second has caused failures 
+        options = ' --screenshot1_sec 2'
+        options += ' --screenshot2_sec 1'
+        options += ' --cooldown_sec 1'
+        options += ' --screenshot1_cmd "screenshot %s"' % screenshot1_generated
+        options += ' --screenshot2_cmd "screenshot %s"' % screenshot2_generated
+
+        utils.system(exefile + " " + options)
+
+        utils.system("convert -resize '100x100!' %s %s" %
+                     (screenshot1_generated, screenshot1_resized))
+        utils.system("convert -resize '100x100!' %s %s" %
+                     (screenshot2_generated, screenshot2_resized))
+        os.remove(screenshot1_generated)
+        os.remove(screenshot2_generated)
+
+        utils.system("perceptualdiff -verbose %s %s"
+                     % (screenshot1_reference, screenshot1_resized))
+        utils.system("perceptualdiff -verbose %s %s"
+                     % (screenshot2_reference, screenshot2_resized))
diff --git a/client/site_tests/graphics_WindowManagerGraphicsCapture/screenshot1_reference b/client/site_tests/graphics_WindowManagerGraphicsCapture/screenshot1_reference
new file mode 100644
index 0000000..8a19aa9
--- /dev/null
+++ b/client/site_tests/graphics_WindowManagerGraphicsCapture/screenshot1_reference
Binary files differ
diff --git a/client/site_tests/graphics_WindowManagerGraphicsCapture/screenshot2_reference b/client/site_tests/graphics_WindowManagerGraphicsCapture/screenshot2_reference
new file mode 100644
index 0000000..a0c1d32
--- /dev/null
+++ b/client/site_tests/graphics_WindowManagerGraphicsCapture/screenshot2_reference
Binary files differ