Revert of Removed arbitrary 4096 size limit on WebGL canvas backbuffers

Source/core/html/canvas/WebGLRenderingContextBase.cpp

Index: Source/core/html/canvas/WebGLRenderingContextBase.cpp
diff --git a/Source/core/html/canvas/WebGLRenderingContextBase.cpp b/Source/core/html/canvas/WebGLRenderingContextBase.cpp
index e20a1c1a958ab0a611d33b372d6f9ac409fbdf1e..2a4b757f33a1e872db341f6f5b1c68b75369f389 100644
--- a/Source/core/html/canvas/WebGLRenderingContextBase.cpp
+++ b/Source/core/html/canvas/WebGLRenderingContextBase.cpp
@@ -1011,6 +1011,9 @@
     // This is an approximation because at WebGLRenderingContextBase level we don't
     // know if the underlying FBO uses textures or renderbuffers.
     GLint maxSize = std::min(m_maxTextureSize, m_maxRenderbufferSize);
+    // Limit drawing buffer size to 4k to avoid memory exhaustion.
+    const int sizeUpperLimit = 4096;
+    maxSize = std::min(maxSize, sizeUpperLimit);
     GLint maxWidth = std::min(maxSize, m_maxViewportDims[0]);
     GLint maxHeight = std::min(maxSize, m_maxViewportDims[1]);
     width = clamp(width, 1, maxWidth);