--- a/dom/canvas/WebGL2Context.cpp
+++ b/dom/canvas/WebGL2Context.cpp
@@ -157,12 +157,32 @@ WebGLContext::InitWebGL2(FailureReason* 
 
     if (!gl->IsGLES()) {
         // Desktop OpenGL requires the following to be enabled in order to
         // support sRGB operations on framebuffers.
         gl->MakeCurrent();
         gl->fEnable(LOCAL_GL_FRAMEBUFFER_SRGB_EXT);
     }
 
+    //////
+
+    static const GLenum kWebGL2_CompressedFormats[] = {
+        LOCAL_GL_COMPRESSED_R11_EAC,
+        LOCAL_GL_COMPRESSED_SIGNED_R11_EAC,
+        LOCAL_GL_COMPRESSED_RG11_EAC,
+        LOCAL_GL_COMPRESSED_SIGNED_RG11_EAC,
+        LOCAL_GL_COMPRESSED_RGB8_ETC2,
+        LOCAL_GL_COMPRESSED_RGB8_PUNCHTHROUGH_ALPHA1_ETC2,
+        LOCAL_GL_COMPRESSED_RGBA8_ETC2_EAC,
+        LOCAL_GL_COMPRESSED_SRGB8_ALPHA8_ETC2_EAC,
+        LOCAL_GL_COMPRESSED_SRGB8_ETC2,
+        LOCAL_GL_COMPRESSED_SRGB8_PUNCHTHROUGH_ALPHA1_ETC2
+    };
+
+    mCompressedTextureFormats.AppendElements(kWebGL2_CompressedFormats,
+                                             MOZ_ARRAY_LENGTH(kWebGL2_CompressedFormats));
+
+    //////
+
     return true;
 }
 
 } // namespace mozilla

--- a/dom/canvas/WebGLFormats.cpp
+++ b/dom/canvas/WebGLFormats.cpp
@@ -801,17 +801,16 @@ FormatUsageAuthority::CreateForWebGL2(gl
     fnAllowES3TexFormat(FOO(DEPTH_COMPONENT16 ), true, false);
     fnAllowES3TexFormat(FOO(DEPTH_COMPONENT24 ), true, false);
     fnAllowES3TexFormat(FOO(DEPTH_COMPONENT32F), true, false);
     fnAllowES3TexFormat(FOO(DEPTH24_STENCIL8  ), true, false);
     fnAllowES3TexFormat(FOO(DEPTH32F_STENCIL8 ), true, false);
 
     // GLES 3.0.4, p147, table 3.19
     // GLES 3.0.4, p286+, $C.1 "ETC Compressed Texture Image Formats"
-#if ALLOW_ES3_FORMATS
     // Note that all compressed texture formats are filterable:
     // GLES 3.0.4 p161:
     // "[A] texture is complete unless any of the following conditions hold true:
     //  [...]
     //  * The effective internal format specified for the texture arrays is a sized
     //    internal color format that is not texture-filterable (see table 3.13) and [the
     //    mag filter requires filtering]."
     // Compressed formats are not sized internal color formats, and indeed they are not
@@ -821,17 +820,17 @@ FormatUsageAuthority::CreateForWebGL2(gl
     fnAllowES3TexFormat(FOO(COMPRESSED_RGBA8_ETC2_EAC                ), false, true);
     fnAllowES3TexFormat(FOO(COMPRESSED_SRGB8_ALPHA8_ETC2_EAC         ), false, true);
     fnAllowES3TexFormat(FOO(COMPRESSED_R11_EAC                       ), false, true);
     fnAllowES3TexFormat(FOO(COMPRESSED_RG11_EAC                      ), false, true);
     fnAllowES3TexFormat(FOO(COMPRESSED_SIGNED_R11_EAC                ), false, true);
     fnAllowES3TexFormat(FOO(COMPRESSED_SIGNED_RG11_EAC               ), false, true);
     fnAllowES3TexFormat(FOO(COMPRESSED_RGB8_PUNCHTHROUGH_ALPHA1_ETC2 ), false, true);
     fnAllowES3TexFormat(FOO(COMPRESSED_SRGB8_PUNCHTHROUGH_ALPHA1_ETC2), false, true);
-#endif
+
 #undef FOO
 
     // GLES 3.0.4, p206, "Required Renderbuffer Formats":
     // "Implementations are also required to support STENCIL_INDEX8. Requesting this
     //  internal format for a renderbuffer will allocate at least 8 stencil bit planes."
 
     auto usage = ptr->EditUsage(EffectiveFormat::STENCIL_INDEX8);
     usage->isRenderable = true;