Revert "OpenGL: delete shaders and pipelines when they are not used any longer"

This reverts commit a57c1db878.

It produces a GL_INVALID_VALUE in ColorStateTest.ColorWriteMask

BUG=dawn:529

Change-Id: I3511057daf24baaf895b86cbda2a3a21e58d77fb
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/65384
Auto-Submit: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Ben Clayton <bclayton@google.com>
Commit-Queue: Corentin Wallez <cwallez@chromium.org>

src/dawn_native/opengl/ComputePipelineGL.cpp

@@ -27,10 +27,6 @@ namespace dawn_native { namespace opengl {
         return pipeline;
     }
 
-    ComputePipeline::~ComputePipeline() {
-        DeleteProgram(ToBackend(GetDevice())->gl);
-    }
-
     MaybeError ComputePipeline::Initialize() {
         DAWN_TRY(
             InitializeBase(ToBackend(GetDevice())->gl, ToBackend(GetLayout()), GetAllStages()));

src/dawn_native/opengl/ComputePipelineGL.h

@@ -35,7 +35,7 @@ namespace dawn_native { namespace opengl {
 
       private:
         using ComputePipelineBase::ComputePipelineBase;
-        ~ComputePipeline() override;
+        ~ComputePipeline() override = default;
         MaybeError Initialize() override;
     };
 

src/dawn_native/opengl/PipelineGL.cpp

@@ -87,7 +87,6 @@ namespace dawn_native { namespace opengl {
         // Create an OpenGL shader for each stage and gather the list of combined samplers.
         PerStage<CombinedSamplerInfo> combinedSamplers;
         bool needsDummySampler = false;
-        std::vector<GLuint> glShaders;
         for (SingleShaderStage stage : IterateStages(activeStages)) {
             const ShaderModule* module = ToBackend(stages[stage].module.Get());
             std::string glsl;
@@ -97,7 +96,6 @@ namespace dawn_native { namespace opengl {
             GLuint shader;
             DAWN_TRY_ASSIGN(shader, CreateShader(gl, GLShaderType(stage), glsl.c_str()));
             gl.AttachShader(mProgram, shader);
-            glShaders.push_back(shader);
         }
 
         if (needsDummySampler) {
@@ -180,19 +178,9 @@ namespace dawn_native { namespace opengl {
 
             textureUnit++;
         }
-
-        for (GLuint glShader : glShaders) {
-            gl.DetachShader(mProgram, glShader);
-            gl.DeleteShader(glShader);
-        }
-
         return {};
     }
 
-    void PipelineGL::DeleteProgram(const OpenGLFunctions& gl) {
-        gl.DeleteProgram(mProgram);
-    }
-
     const std::vector<PipelineGL::SamplerUnit>& PipelineGL::GetTextureUnitsForSampler(
         GLuint index) const {
         ASSERT(index < mUnitsForSamplers.size());

src/dawn_native/opengl/PipelineGL.h

@@ -47,12 +47,12 @@ namespace dawn_native { namespace opengl {
         const std::vector<GLuint>& GetTextureUnitsForTextureView(GLuint index) const;
         GLuint GetProgramHandle() const;
 
-      protected:
         void ApplyNow(const OpenGLFunctions& gl);
+
+      protected:
         MaybeError InitializeBase(const OpenGLFunctions& gl,
                                   const PipelineLayout* layout,
                                   const PerStage<ProgrammableStage>& stages);
-        void DeleteProgram(const OpenGLFunctions& gl);
 
       private:
         GLuint mProgram;

src/dawn_native/opengl/RenderPipelineGL.cpp

@@ -238,7 +238,6 @@ namespace dawn_native { namespace opengl {
         const OpenGLFunctions& gl = ToBackend(GetDevice())->gl;
         gl.DeleteVertexArrays(1, &mVertexArrayObject);
         gl.BindVertexArray(0);
-        DeleteProgram(gl);
     }
 
     GLenum RenderPipeline::GetGLPrimitiveTopology() const {