Set cask and download DSL values on requirements.

Closes Homebrew/homebrew#35257.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>

Library/Homebrew/requirements.rb

@@ -60,28 +60,20 @@ end
 
 class TeXDependency < Requirement
   fatal true
+  cask "mactex"
+  download "http://www.tug.org/mactex/"
 
   satisfy { which('tex') || which('latex') }
 
-  def message;
-    if File.exist?("/usr/texbin")
-      texbin_path = "/usr/texbin"
-    else
-      texbin_path = "its bin directory"
-    end
-
-    <<-EOS.undent
+  def message
+    s = <<-EOS.undent
       A LaTeX distribution is required for Homebrew to install this formula.
 
-    You can install MacTeX distribution with:
-      brew cask install mactex
-
-    Or from:
-      http://www.tug.org/mactex/
-
       Make sure that "/usr/texbin", or the location you installed it to, is in
       your PATH before proceeding.
     EOS
+    s += super
+    s
   end
 end
 
@@ -120,6 +112,9 @@ end
 
 class JavaDependency < Requirement
   fatal true
+  cask "java"
+  download "http://www.oracle.com/technetwork/java/javase/downloads/index.html"
+
   satisfy { java_version }
 
   def initialize(tags)
@@ -136,15 +131,9 @@ class JavaDependency < Requirement
   def message
     version_string = " #{@version}" if @version
 
-    <<-EOS.undent
-      Java#{version_string} is required to install this formula.
-
-      You can install the Java Development Kit (JDK) with:
-        brew cask install java
-
-      Or from:
-        http://www.oracle.com/technetwork/java/javase/downloads/index.html
-    EOS
+    s = "Java#{version_string} is required to install this formula."
+    s += super
+    s
   end
 end
 

Library/Homebrew/requirements/osxfuse_dependency.rb

@@ -3,6 +3,9 @@ require "requirement"
 class OsxfuseDependency < Requirement
   fatal true
   default_formula "osxfuse"
+  cask "osxfuse"
+  download "https://osxfuse"
+
   satisfy { Formula["osxfuse"].installed? || self.class.binary_osxfuse_installed? }
 
   def self.binary_osxfuse_installed?
@@ -12,7 +15,6 @@ class OsxfuseDependency < Requirement
   env do
     ENV.append_path "PKG_CONFIG_PATH", HOMEBREW_PREFIX/"Library/ENV/pkgconfig/fuse"
   end
-
 end
 
 class ConflictsWithBinaryOsxfuse < Requirement

Library/Homebrew/requirements/python_dependency.rb

@@ -3,6 +3,7 @@ require "language/python"
 class PythonDependency < Requirement
   fatal true
   default_formula "python"
+  cask "python"
 
   satisfy :build_env => false do
     python = which_python
@@ -51,6 +52,7 @@ end
 class Python3Dependency < PythonDependency
   fatal true
   default_formula "python3"
+  cask "python3"
 
   satisfy(:build_env => false) { which_python }
 

Library/Homebrew/requirements/tuntap_dependency.rb

@@ -3,6 +3,7 @@ require "requirement"
 class TuntapDependency < Requirement
   fatal true
   default_formula "tuntap"
+  cask "tuntap"
   satisfy { self.class.binary_tuntap_installed? || Formula["tuntap"].installed? }
 
   def self.binary_tuntap_installed?

Library/Homebrew/requirements/x11_dependency.rb

@@ -5,6 +5,8 @@ class X11Dependency < Requirement
   attr_reader :min_version
 
   fatal true
+  cask "xquartz"
+  download "https://xquartz.macosforge.org"
 
   env { ENV.x11 }
 
@@ -24,13 +26,10 @@ class X11Dependency < Requirement
     MacOS::XQuartz.installed? && min_version <= Version.new(MacOS::XQuartz.version)
   end
 
-  def message; <<-EOS.undent
-    You can install XQuartz#{@min_version_string} with:
-      brew cask install xquartz
-
-    Or from:
-      https://xquartz.macosforge.org
-    EOS
+  def message
+    s = "XQuartz#{@min_version_string} is required to install this formula."
+    s += super
+    s
   end
 
   def <=> other