Implement support textured path rendering in gpu command buffer for CHROMIUM_path_rendering. Add the concept of "fragment input" to the system: a fragment input is a fragment shader varying in the case the fragment shader of a shader program is used without the vertex shader. A fragment input can be referenced by the varying name in the shader code. As the vertex shader is skipped during path rendering, the fragment inputs will be populated with the functions added in this commit. Add following functions to the command buffer: BindFragmentInputLocationCHROMIUM ProgramPathFragmentInputGenCHROMIUM BindFragmentInputLocationCHROMIUM will bind a fragment input to a location supplied by the caller. The fragment input is identified by the varying name. The semantics of the call are similar to BindUniformLocationCHROMIUM, but of course the location bound with BindFragmentInputLocationCHROMIUM is part of fragment input location range. Concretely, BindFragmentInputLocationCHROMIUM is used to obtain a location to pass to ProgramPathFragmentInputGenCHROMIUM. ProgramPathFragmentInputGenCHROMIUM sets the "path fragment input generator" property of the fragment input identified by the location passed by the caller. This property, together with global path modelview transform and global path projection transform is used to generate the value of the fragment input. Concretely, ProgramPathFragmentInputGenCHROMIUM is used to obtain a value in the fragment input that is somehow relative to the fragment position in on the path coverage. When drawing normal vertex-based primitives, shading is done by setting the vertex position with an attribute or an uniform, the transform with an attribute or an uniform, transforming the position with the transform in vertex shader and interpolating the values for fragment varying. When drawing a path, the path position is set with projection and modelview matrix, transform is set with ProgramPathFragmentInputGenCHROMIUM and the system will then fill the fragment input based on the location of the fragment in the area covered by the path and the input generator mode (eye space or model space). Implement the BindFragmentInputLocationCHROMIUM by the means of program interface query API, which is part of OpenGL 4.3 and OpenGL ES 3.1. Alternatively, OpenGL pre 4.3 can have the functionality through ARB_program_interface_query. glGetProgramInterfaceiv, glGetProgramResourceiv, glGetProgramResourceName and glGetProgramResourceLocation are used to query the program for its fragment inputs after successful link. This list is then used to map caller-bound locations to actual locations. This is similar to existing logic for bound uniform and attribute locations. Note: this patch does not provide getter for fragment input location, so unbound fragment und locations to actual locations. This is similar to existing logic for bound uniform and attribute locations. Note: this patch does not provide getter for fragment input location, so unbound fragment inputs can not be used by the caller. Providing this would require implementation of the interface query API, which is too elaborate to be implemented without proper consumers. Note: as the query API is not available for the client, the fragment input information is not serialized between client and the service. Implement the ProgramPathFragmentInputGenCHROMIUM by means of NV_path_rendering ProgramPathFragmentInputGenNV. This is part of NV_path_rendering spec version 1.3. Changes gpu::gles2::ProgramManager to reference FeatureInfo of the ContextGroup, because the queries for the fragment input is only done if path rendering is enabled. Changes program_manager_unittests to have a common test base class. Remove some client/service program id constants from test functions that shadow ProgramManagerWithShader constants. Instead, use the common constants defined in the test class. Re-organizes the test classes to be able to use common ProgramManager from the test base class. Initialize the ProgramManager in SetUp phase. This is done to be able to provide custom FeatureInfo objects to the ProgramManager. This is done in order to test the code that is run only if path rendering is enabled. Changes NV_path_rendering to be enabled only for ES 3.1 contexts. The extension spec does not spec the full needed program_interface_query functionality. Thus the location info is only obtainable from 3.1 contexts. Sets the driver version needed for the feature as 346. The 346.35 driver is the version in which glGetProgramInterfaceiv(.._, GL_FRAGMENT_INPUT_NV, GL_ACTIVE_RESOURCES, ..) works. BUG=344330 Review URL: https://codereview.chromium.org/527233002 Cr-Commit-Position: refs/heads/master@{#357321}