Remove third_party/golang.org/x/mobile as it is no longer used with Go 1.5.

third_party/go/src/golang.org/x/mobile/geom/geom.go

-// Copyright 2014 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-/*
-Package geom defines a two-dimensional coordinate system.
-
-The coordinate system is based on an left-handed Cartesian plane.
-That is, X increases to the right and Y increases down. For (x,y),
-
-        (0,0) → (1,0)
-          ↓   ↘
-        (0,1)   (1,1)
-
-The display window places the origin (0, 0) in the upper-left corner of
-the screen. Positions on the plane are measured in typographic points,
-1/72 of an inch, which is represented by the Pt type.
-
-Any interface that draws to the screen using types from the geom package
-scales the number of pixels to maintain a Pt as 1/72 of an inch.
-*/
-package geom // import "golang.org/x/mobile/geom"
-
-/*
-Notes on the various underlying coordinate systems.
-
-Both Android and iOS (UIKit) use upper-left-origin coordinate systems
-with for events, however they have different units.
-
-UIKit measures distance in points. A point is a single-pixel on a
-pre-Retina display. UIKit maintains a scale factor that to turn points
-into pixels. On current retina devices, the scale factor is 2.0.
-
-A UIKit point does not correspond to a fixed physical distance, as the
-iPhone has a 163 DPI/PPI (326 PPI retina) display, and the iPad has a
-132 PPI (264 retina) display. Points are 32-bit floats.
-
-Even though point is the official UIKit term, they are commonly called
-pixels. Indeed, the units were equivalent until the retina display was
-introduced.
-
-N.b. as a UIKit point is unrelated to a typographic point, it is not
-related to this packages's Pt and Point types.
-
-More details about iOS drawing:
-
-https://developer.apple.com/library/ios/documentation/2ddrawing/conceptual/drawingprintingios/GraphicsDrawingOverview/GraphicsDrawingOverview.html
-
-Android uses pixels. Sub-pixel precision is possible, so pixels are
-represented as 32-bit floats. The ACONFIGURATION_DENSITY enum provides
-the screen DPI/PPI, which varies frequently between devices.
-
-It would be tempting to adopt the pixel, given the clear pixel/DPI split
-in the core android events API. However, the plot thickens:
-
-http://developer.android.com/training/multiscreen/screendensities.html
-
-Android promotes the notion of a density-independent pixel in many of
-their interfaces, often prefixed by "dp". 1dp is a real physical length,
-as "independent" means it is assumed to be 1/160th of an inch and is
-adjusted for the current screen.
-
-In addition, android has a scale-indepdendent pixel used for expressing
-a user's preferred text size. The user text size preference is a useful
-notion not yet expressed in the geom package.
-
-For the sake of clarity when working across platforms, the geom package
-tries to put distance between it and the word pixel.
-*/
-
-import "fmt"
-
-// Pt is a length.
-//
-// The unit Pt is a typographical point, 1/72 of an inch (0.3527 mm).
-//
-// It can be be converted to a length in current device pixels by
-// multiplying with PixelsPerPt after app initialization is complete.
-type Pt float32
-
-// Px converts the length to current device pixels.
-func (p Pt) Px() float32 { return float32(p) * PixelsPerPt }
-
-// String returns a string representation of p like "3.2pt".
-func (p Pt) String() string { return fmt.Sprintf("%.2fpt", p) }
-
-// Point is a point in a two-dimensional plane.
-type Point struct {
-        X, Y Pt
-}
-
-// String returns a string representation of p like "(1.2,3.4)".
-func (p Point) String() string { return fmt.Sprintf("(%.2f,%.2f)", p.X, p.Y) }
-
-// A Rectangle is region of points.
-// The top-left point is Min, and the bottom-right point is Max.
-type Rectangle struct {
-        Min, Max Point
-}
-
-// String returns a string representation of r like "(3,4)-(6,5)".
-func (r Rectangle) String() string { return r.Min.String() + "-" + r.Max.String() }
-
-// PixelsPerPt is the number of pixels in a single Pt on the current device.
-//
-// There are a wide variety of pixel densities in existing phones and
-// tablets, so apps should be written to expect various non-integer
-// PixelsPerPt values. In general, work in Pt.
-//
-// Not valid until app initialization has completed.
-var PixelsPerPt float32
-
-// Width is the width of the device screen.
-// Not valid until app initialization has completed.
-var Width Pt
-
-// Height is the height of the device screen.
-// Not valid until app initialization has completed.
-var Height Pt