Cleanup: Remove unused enable_eglimage variable and #define.

build/common.gypi

Index: build/common.gypi
diff --git a/build/common.gypi b/build/common.gypi
index 708e12c2aa3f6ae9ff536f5c7a71f33ca6d4f34f..dcba6de6660c379620aad8e577baa537a34c42e3 100644
--- a/build/common.gypi
+++ b/build/common.gypi
@@ -1354,9 +1354,6 @@
     # Enable new NPDevice API.
     'enable_new_npdevice_api%': 0,
 
-    # Enable EGLImage support in OpenMAX
-    'enable_eglimage%': 1,
-
     # .gyp files or targets should set chromium_code to 1 if they build
     # Chromium-specific code, as opposed to external code.  This variable is
     # used to control such things as the set of warnings to enable, and
@@ -2753,11 +2750,6 @@
           }],
         ],
       }],
-      ['enable_eglimage==1', {
-        'defines': [
-          'ENABLE_EGLIMAGE=1',
-        ],
-      }],
       ['asan==1', {
         'defines': [
           'ADDRESS_SANITIZER',