Add PDF extension support (issue #1565)

tools/distrib/linux/README.redistrib.txt

@@ -1,44 +1,62 @@
 REDISTRIBUTION
 --------------
 
-This binary distribution contains the below components. Components listed under
-the "required" section must be redistributed with all applications using CEF.
-Components listed under the "optional" section may be excluded if the related
-features will not be used.
+This binary distribution contains the below components.
 
 Required components:
 
-* CEF core library
-    libcef.so
+The following components are required. CEF will not function without them.
 
-* Unicode support
-    icudtl.dat
+* CEF core library.
+  * libcef.so
 
-* V8 initial snapshot
-    natives_blob.bin
-    snapshot_blob.bin
+* Unicode support data.
+  * icudtl.dat
+
+* V8 snapshot data.
+  * natives_blob.bin
+  * snapshot_blob.bin
 
 Optional components:
 
-* Localized resources
-    locales/
-  Note: Contains localized strings for WebKit UI controls. A .pak file is loaded
-  from this folder based on the value of environment variables which are read
-  with the following precedence order: LANGUAGE, LC_ALL, LC_MESSAGES and LANG.
-  Only configured locales need to be distributed. If no locale is configured the
-  default locale of "en-US" will be used. Locale file loading can be disabled
-  completely using CefSettings.pack_loading_disabled. The locales folder path
-  can be customized using CefSettings.locales_dir_path.
+The following components are optional. If they are missing CEF will continue to
+run but any related functionality may become broken or disabled.
 
-* Other resources
-    cef.pak
-    cef_100_percent.pak
-    cef_200_percent.pak
-    devtools_resources.pak
-  Note: Contains WebKit image and inspector resources. Pack file loading can be
-  disabled completely using CefSettings.pack_loading_disabled. The resources
-  directory path can be customized using CefSettings.resources_dir_path.
+* Localized resources.
+  Locale file loading can be disabled completely using
+  CefSettings.pack_loading_disabled. The locales directory path can be
+  customized using CefSettings.locales_dir_path. 
+ 
+  * locales/
+    Directory containing localized resources used by CEF, Chromium and Blink. A
+    .pak file is loaded from this directory based on the value of environment
+    variables which are read with the following precedence order: LANGUAGE,
+    LC_ALL, LC_MESSAGES and LANG. Only configured locales need to be
+    distributed. If no locale is configured the default locale of "en-US" will
+    be used. Without these files arbitrary Web components may display
+    incorrectly.
 
-* FFmpeg audio and video support
-    libffmpegsumo.so
-  Note: Without this component HTML5 audio and video will not function.
+* Other resources.
+  Pack file loading can be disabled completely using
+  CefSettings.pack_loading_disabled. The resources directory path can be
+  customized using CefSettings.resources_dir_path.
+
+  * cef.pak
+  * cef_100_percent.pak
+  * cef_200_percent.pak
+    These files contain non-localized resources used by CEF, Chromium and Blink.
+    Without these files arbitrary Web components may display incorrectly.
+
+  * cef_extensions.pak
+    This file contains non-localized resources required for extension loading.
+    Pass the `--disable-extensions` command-line flag to disable use of this
+    file. Without this file components that depend on the extension system,
+    such as the PDF viewer, will not function.
+
+  * devtools_resources.pak
+    This file contains non-localized resources required for Chrome Developer
+    Tools. Without this file Chrome Developer Tools will not function.
+
+* FFmpeg audio and video support.
+  * libffmpegsumo.so
+    Without this file HTML5 audio and video will not function.