Primitive restart fixed

SwiftShader wasn't correctly handling having no restart indices
in the index buffer while having primitive restart enabled. In
the WebGL 2 conformance tests, the reference image is also
computed while primitive restart is on, which means that
Context::drawElements() may modify the internal primitive type,
so indices must be adjusted to reflect that change, even if no
restart indices are present in the index buffer.

Fixes all WebGL 2 tests in:
all/deqp/functional/gles3/primitiverestart

Change-Id: I24f129e0f7bd42b5037b74617b48a32621440ddb
Reviewed-on: https://swiftshader-review.googlesource.com/16548
Tested-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>

src/OpenGL/libGLESv2/IndexDataManager.cpp

diff --git a/src/OpenGL/libGLESv2/IndexDataManager.cpp b/src/OpenGL/libGLESv2/IndexDataManager.cpp
index a32b7d1..55c15b2 100644
--- a/src/OpenGL/libGLESv2/IndexDataManager.cpp
+++ b/src/OpenGL/libGLESv2/IndexDataManager.cpp
@@ -65,7 +65,8 @@
 
 inline GLsizei getNumIndices(const std::vector<GLsizei>& restartIndices, size_t i, GLsizei count)
 {
-	return (i == 0) ? restartIndices[0] : ((i == restartIndices.size()) ? (count - restartIndices[i - 1] - 1) : (restartIndices[i] - restartIndices[i - 1] - 1));
+	return restartIndices.empty() ? count :
+	       ((i == 0) ? restartIndices[0] : ((i == restartIndices.size()) ? (count - restartIndices[i - 1] - 1) : (restartIndices[i] - restartIndices[i - 1] - 1)));
 }
 
 void copyIndices(GLenum mode, GLenum type, const std::vector<GLsizei>& restartIndices, const void *input, GLsizei count, void* output)
@@ -290,11 +291,6 @@
 
 	std::vector<GLsizei>* restartIndices = primitiveRestart ? new std::vector<GLsizei>() : nullptr;
 	computeRange(type, indices, count, &translated->minIndex, &translated->maxIndex, restartIndices);
-	if(restartIndices && restartIndices->empty())
-	{
-		delete restartIndices;
-		restartIndices = nullptr;
-	}
 
 	StreamingIndexBuffer *streamingBuffer = mStreamingBuffer;